class Sequel::Dataset
A dataset represents an SQL
query. Datasets can be used to select, insert, update and delete records.
Query
results are always retrieved on demand, so a dataset can be kept around and reused indefinitely (datasets never cache results):
my_posts = DB[:posts].where(author: 'david') # no records are retrieved my_posts.all # records are retrieved my_posts.all # records are retrieved again
Datasets are frozen and use a functional style where modification methods return modified copies of the the dataset. This allows you to reuse datasets:
posts = DB[:posts] davids_posts = posts.where(author: 'david') old_posts = posts.where{stamp < Date.today - 7} davids_old_posts = davids_posts.where{stamp < Date.today - 7}
Datasets are Enumerable objects, so they can be manipulated using many of the Enumerable methods, such as map
and inject
. Note that there are some methods that Dataset
defines that override methods defined in Enumerable and result in different behavior, such as select
and group_by
.
For more information, see the “Dataset Basics” guide.
Constants
- OPTS
- TRUE_FREEZE
-
Whether
Dataset#freeze
can actually freeze datasets. True only on ruby 2.4+, as it requires clone(freeze: false)
1 - Methods that return modified datasets
↑ topConstants
- COLUMN_CHANGE_OPTS
-
The dataset options that require the removal of cached columns if changed.
- CONDITIONED_JOIN_TYPES
-
These symbols have _join methods created (e.g. inner_join) that call
join_table
with the symbol, passing along the arguments and block from the method call. - EMPTY_ARRAY
- EXTENSIONS
-
Hash
of extension name symbols to callable objects to load the extension into theDataset
object (usually by extending it with a module defined in the extension). - EXTENSION_MODULES
-
Hash
of extension name symbols to modules to load to implement the extension. - JOIN_METHODS
-
All methods that return modified datasets with a joined table added.
- NON_SQL_OPTIONS
-
Which options don’t affect the
SQL
generation. Used by simple_select_all? to determine if this is a simple SELECT * FROM table. - QUERY_METHODS
-
Methods that return modified datasets
- SIMPLE_SELECT_ALL_ALLOWED_FROM
-
From types allowed to be considered a simple_select_all
- UNCONDITIONED_JOIN_TYPES
-
These symbols have _join methods created (e.g. natural_join). They accept a table argument and options hash which is passed to
join_table
, and they raise an error if called with a block.
Public Class Methods
Source
# File lib/sequel/dataset/query.rb 55 def self.register_extension(ext, mod=nil, &block) 56 if mod 57 raise(Error, "cannot provide both mod and block to Dataset.register_extension") if block 58 if mod.is_a?(Module) 59 block = proc{|ds| ds.extend(mod)} 60 Sequel::Database.register_extension(ext){|db| db.extend_datasets(mod)} 61 Sequel.synchronize{EXTENSION_MODULES[ext] = mod} 62 else 63 block = mod 64 end 65 end 66 67 unless mod.is_a?(Module) 68 Sequel::Deprecation.deprecate("Providing a block or non-module to Sequel::Dataset.register_extension is deprecated and support for it will be removed in Sequel 6.") 69 end 70 71 Sequel.synchronize{EXTENSIONS[ext] = block} 72 end
Register an extension callback for Dataset
objects. ext should be the extension name symbol, and mod should be a Module that will be included in the dataset’s class. This also registers a Database
extension that will extend all of the database’s datasets.
Public Instance Methods
Save original clone implementation, as some other methods need to call it internally.
Source
# File lib/sequel/dataset/query.rb 90 def clone(opts = nil || (return self)) 91 # return self used above because clone is called by almost all 92 # other query methods, and it is the fastest approach 93 c = super(:freeze=>false) 94 c.opts.merge!(opts) 95 unless opts.each_key{|o| break if COLUMN_CHANGE_OPTS.include?(o)} 96 c.clear_columns_cache 97 end 98 c.freeze 99 end
Returns a new clone of the dataset with the given options merged. If the options changed include options in COLUMN_CHANGE_OPTS
, the cached columns are deleted. This method should generally not be called directly by user code.
Source
# File lib/sequel/dataset/query.rb 129 def distinct(*args, &block) 130 virtual_row_columns(args, block) 131 if args.empty? 132 return self if opts[:distinct] == EMPTY_ARRAY 133 cached_dataset(:_distinct_ds){clone(:distinct => EMPTY_ARRAY)} 134 else 135 raise(InvalidOperation, "DISTINCT ON not supported") unless supports_distinct_on? 136 clone(:distinct => args.freeze) 137 end 138 end
Returns a copy of the dataset with the SQL
DISTINCT clause. The DISTINCT clause is used to remove duplicate rows from the output. If arguments are provided, uses a DISTINCT ON clause, in which case it will only be distinct on those columns, instead of all returned columns. If a block is given, it is treated as a virtual row block, similar to where
. Raises an error if arguments are given and DISTINCT ON is not supported.
DB[:items].distinct # SQL: SELECT DISTINCT * FROM items DB[:items].order(:id).distinct(:id) # SQL: SELECT DISTINCT ON (id) * FROM items ORDER BY id DB[:items].order(:id).distinct{func(:id)} # SQL: SELECT DISTINCT ON (func(id)) * FROM items ORDER BY id
There is support for emulating the DISTINCT ON support in MySQL
, but it does not support the ORDER of the dataset, and also doesn’t work in many cases if the ONLY_FULL_GROUP_BY sql_mode is used, which is the default on MySQL
5.7.5+.
Source
# File lib/sequel/dataset/query.rb 157 def except(dataset, opts=OPTS) 158 raise(InvalidOperation, "EXCEPT not supported") unless supports_intersect_except? 159 raise(InvalidOperation, "EXCEPT ALL not supported") if opts[:all] && !supports_intersect_except_all? 160 compound_clone(:except, dataset, opts) 161 end
Adds an EXCEPT clause using a second dataset object. An EXCEPT compound dataset returns all rows in the current dataset that are not in the given dataset. Raises an InvalidOperation
if the operation is not supported. Options:
- :alias
-
Use the given value as the
from_self
alias - :all
-
Set to true to use EXCEPT ALL instead of EXCEPT, so duplicate rows can occur
- :from_self
-
Set to false to not wrap the returned dataset in a
from_self
, use with care.
DB[:items].except(DB[:other_items]) # SELECT * FROM (SELECT * FROM items EXCEPT SELECT * FROM other_items) AS t1 DB[:items].except(DB[:other_items], all: true, from_self: false) # SELECT * FROM items EXCEPT ALL SELECT * FROM other_items DB[:items].except(DB[:other_items], alias: :i) # SELECT * FROM (SELECT * FROM items EXCEPT SELECT * FROM other_items) AS i
Source
# File lib/sequel/dataset/query.rb 187 def exclude(*cond, &block) 188 add_filter(:where, cond, true, &block) 189 end
Performs the inverse of Dataset#where
. Note that if you have multiple filter conditions, this is not the same as a negation of all conditions.
DB[:items].exclude(category: 'software') # SELECT * FROM items WHERE (category != 'software') DB[:items].exclude(category: 'software', id: 3) # SELECT * FROM items WHERE ((category != 'software') OR (id != 3))
Also note that SQL
uses 3-valued boolean logic (true
, false
, NULL
), so the inverse of a true condition is a false condition, and will still not match rows that were NULL originally. If you take the earlier example:
DB[:items].exclude(category: 'software') # SELECT * FROM items WHERE (category != 'software')
Note that this does not match rows where category
is NULL
. This is because NULL
is an unknown value, and you do not know whether or not the NULL
category is software
. You can explicitly specify how to handle NULL
values if you want:
DB[:items].exclude(Sequel.~(category: nil) & {category: 'software'}) # SELECT * FROM items WHERE ((category IS NULL) OR (category != 'software'))
Source
# File lib/sequel/dataset/query.rb 198 def exclude_having(*cond, &block) 199 add_filter(:having, cond, true, &block) 200 end
Inverts the given conditions and adds them to the HAVING clause.
DB[:items].select_group(:name).exclude_having{count(name) < 2} # SELECT name FROM items GROUP BY name HAVING (count(name) >= 2)
See documentation for exclude for how inversion is handled in regards to SQL
3-valued boolean logic.
Source
# File lib/sequel/dataset/query.rb 206 def extension(*exts) 207 Sequel.extension(*exts) 208 mods = exts.map{|ext| Sequel.synchronize{EXTENSION_MODULES[ext]}} 209 if mods.all? 210 with_extend(*mods) 211 else 212 with_extend(DeprecatedSingletonClassMethods).extension(*exts) 213 end 214 end
Return a clone of the dataset loaded with the given dataset extensions. If no related extension file exists or the extension does not have specific support for Dataset
objects, an error will be raised.
Source
# File lib/sequel/dataset/query.rb 226 def filter(*cond, &block) 227 where(*cond, &block) 228 end
Alias for where.
Source
# File lib/sequel/dataset/query.rb 233 def for_update 234 return self if opts[:lock] == :update 235 cached_dataset(:_for_update_ds){lock_style(:update)} 236 end
Returns a cloned dataset with a :update lock style.
DB[:table].for_update # SELECT * FROM table FOR UPDATE
Source
# File lib/sequel/dataset/query.rb 247 def from(*source, &block) 248 virtual_row_columns(source, block) 249 table_alias_num = 0 250 ctes = nil 251 source.map! do |s| 252 case s 253 when Dataset 254 if hoist_cte?(s) 255 ctes ||= [] 256 ctes += s.opts[:with] 257 s = s.clone(:with=>nil) 258 end 259 SQL::AliasedExpression.new(s, dataset_alias(table_alias_num+=1)) 260 when Symbol 261 sch, table, aliaz = split_symbol(s) 262 if aliaz 263 s = sch ? SQL::QualifiedIdentifier.new(sch, table) : SQL::Identifier.new(table) 264 SQL::AliasedExpression.new(s, aliaz.to_sym) 265 else 266 s 267 end 268 else 269 s 270 end 271 end 272 o = {:from=>source.empty? ? nil : source.freeze} 273 o[:with] = ((opts[:with] || EMPTY_ARRAY) + ctes).freeze if ctes 274 o[:num_dataset_sources] = table_alias_num if table_alias_num > 0 275 clone(o) 276 end
Returns a copy of the dataset with the source changed. If no source is given, removes all tables. If multiple sources are given, it is the same as using a CROSS JOIN (cartesian product) between all tables. If a block is given, it is treated as a virtual row block, similar to where
.
DB[:items].from # SQL: SELECT * DB[:items].from(:blah) # SQL: SELECT * FROM blah DB[:items].from(:blah, :foo) # SQL: SELECT * FROM blah, foo DB[:items].from{fun(arg)} # SQL: SELECT * FROM fun(arg)
Source
# File lib/sequel/dataset/query.rb 295 def from_self(opts=OPTS) 296 fs = {} 297 @opts.keys.each{|k| fs[k] = nil unless non_sql_option?(k)} 298 pr = proc do 299 c = clone(fs).from(opts[:alias] ? as(opts[:alias], opts[:column_aliases]) : self) 300 if cols = _columns 301 c.send(:columns=, cols) 302 end 303 c 304 end 305 306 opts.empty? ? cached_dataset(:_from_self_ds, &pr) : pr.call 307 end
Returns a dataset selecting from the current dataset. Options:
- :alias
-
Controls the alias of the table
- :column_aliases
-
Also aliases columns, using derived column lists. Only used in conjunction with :alias.
ds = DB[:items].order(:name).select(:id, :name) # SELECT id,name FROM items ORDER BY name ds.from_self # SELECT * FROM (SELECT id, name FROM items ORDER BY name) AS t1 ds.from_self(alias: :foo) # SELECT * FROM (SELECT id, name FROM items ORDER BY name) AS foo ds.from_self(alias: :foo, column_aliases: [:c1, :c2]) # SELECT * FROM (SELECT id, name FROM items ORDER BY name) AS foo(c1, c2)
Source
# File lib/sequel/dataset/query.rb 344 def grep(columns, patterns, opts=OPTS) 345 column_op = opts[:all_columns] ? :AND : :OR 346 if opts[:all_patterns] 347 conds = Array(patterns).map do |pat| 348 SQL::BooleanExpression.new(column_op, *Array(columns).map{|c| SQL::StringExpression.like(c, pat, opts)}) 349 end 350 where(SQL::BooleanExpression.new(:AND, *conds)) 351 else 352 conds = Array(columns).map do |c| 353 SQL::BooleanExpression.new(:OR, *Array(patterns).map{|pat| SQL::StringExpression.like(c, pat, opts)}) 354 end 355 where(SQL::BooleanExpression.new(column_op, *conds)) 356 end 357 end
Match any of the columns to any of the patterns. The terms can be strings (which use LIKE) or regular expressions if the database supports that. Note that the total number of pattern matches will be Array(columns).length * Array(terms).length, which could cause performance issues.
Options (all are boolean):
- :all_columns
-
All columns must be matched to any of the given patterns.
- :all_patterns
-
All patterns must match at least one of the columns.
- :case_insensitive
-
Use a case insensitive pattern match (the default is case sensitive if the database supports it).
If both :all_columns and :all_patterns are true, all columns must match all patterns.
Examples:
dataset.grep(:a, '%test%') # SELECT * FROM items WHERE (a LIKE '%test%' ESCAPE '\') dataset.grep([:a, :b], %w'%test% foo') # SELECT * FROM items WHERE ((a LIKE '%test%' ESCAPE '\') OR (a LIKE 'foo' ESCAPE '\') # OR (b LIKE '%test%' ESCAPE '\') OR (b LIKE 'foo' ESCAPE '\')) dataset.grep([:a, :b], %w'%foo% %bar%', all_patterns: true) # SELECT * FROM a WHERE (((a LIKE '%foo%' ESCAPE '\') OR (b LIKE '%foo%' ESCAPE '\')) # AND ((a LIKE '%bar%' ESCAPE '\') OR (b LIKE '%bar%' ESCAPE '\'))) dataset.grep([:a, :b], %w'%foo% %bar%', all_columns: true) # SELECT * FROM a WHERE (((a LIKE '%foo%' ESCAPE '\') OR (a LIKE '%bar%' ESCAPE '\')) # AND ((b LIKE '%foo%' ESCAPE '\') OR (b LIKE '%bar%' ESCAPE '\'))) dataset.grep([:a, :b], %w'%foo% %bar%', all_patterns: true, all_columns: true) # SELECT * FROM a WHERE ((a LIKE '%foo%' ESCAPE '\') AND (b LIKE '%foo%' ESCAPE '\') # AND (a LIKE '%bar%' ESCAPE '\') AND (b LIKE '%bar%' ESCAPE '\'))
Source
# File lib/sequel/dataset/query.rb 366 def group(*columns, &block) 367 virtual_row_columns(columns, block) 368 clone(:group => (columns.compact.empty? ? nil : columns.freeze)) 369 end
Returns a copy of the dataset with the results grouped by the value of the given columns. If a block is given, it is treated as a virtual row block, similar to where
.
DB[:items].group(:id) # SELECT * FROM items GROUP BY id DB[:items].group(:id, :name) # SELECT * FROM items GROUP BY id, name DB[:items].group{[a, sum(b)]} # SELECT * FROM items GROUP BY a, sum(b)
Source
# File lib/sequel/dataset/query.rb 397 def group_and_count(*columns, &block) 398 select_group(*columns, &block).select_append(COUNT_OF_ALL_AS_COUNT) 399 end
Returns a dataset grouped by the given column with count by group. Column aliases may be supplied, and will be included in the select clause. If a block is given, it is treated as a virtual row block, similar to where
.
Examples:
DB[:items].group_and_count(:name).all # SELECT name, count(*) AS count FROM items GROUP BY name # => [{:name=>'a', :count=>1}, ...] DB[:items].group_and_count(:first_name, :last_name).all # SELECT first_name, last_name, count(*) AS count FROM items GROUP BY first_name, last_name # => [{:first_name=>'a', :last_name=>'b', :count=>1}, ...] DB[:items].group_and_count(Sequel[:first_name].as(:name)).all # SELECT first_name AS name, count(*) AS count FROM items GROUP BY first_name # => [{:name=>'a', :count=>1}, ...] DB[:items].group_and_count{substr(:first_name, 1, 1).as(:initial)}.all # SELECT substr(first_name, 1, 1) AS initial, count(*) AS count FROM items GROUP BY substr(first_name, 1, 1) # => [{:initial=>'a', :count=>1}, ...]
Source
# File lib/sequel/dataset/query.rb 407 def group_append(*columns, &block) 408 columns = @opts[:group] + columns if @opts[:group] 409 group(*columns, &block) 410 end
Returns a copy of the dataset with the given columns added to the list of existing columns to group on. If no existing columns are present this method simply sets the columns as the initial ones to group on.
DB[:items].group_append(:b) # SELECT * FROM items GROUP BY b DB[:items].group(:a).group_append(:b) # SELECT * FROM items GROUP BY a, b
Source
# File lib/sequel/dataset/query.rb 372 def group_by(*columns, &block) 373 group(*columns, &block) 374 end
Alias of group
Source
# File lib/sequel/dataset/query.rb 413 def group_cube 414 raise Error, "GROUP BY CUBE not supported on #{db.database_type}" unless supports_group_cube? 415 clone(:group_options=>:cube) 416 end
Adds the appropriate CUBE syntax to GROUP BY.
Source
# File lib/sequel/dataset/query.rb 419 def group_rollup 420 raise Error, "GROUP BY ROLLUP not supported on #{db.database_type}" unless supports_group_rollup? 421 clone(:group_options=>:rollup) 422 end
Adds the appropriate ROLLUP syntax to GROUP BY.
Source
# File lib/sequel/dataset/query.rb 425 def grouping_sets 426 raise Error, "GROUP BY GROUPING SETS not supported on #{db.database_type}" unless supports_grouping_sets? 427 clone(:group_options=>:"grouping sets") 428 end
Adds the appropriate GROUPING SETS syntax to GROUP BY.
Source
# File lib/sequel/dataset/query.rb 434 def having(*cond, &block) 435 add_filter(:having, cond, &block) 436 end
Returns a copy of the dataset with the HAVING conditions changed. See where
for argument types.
DB[:items].group(:sum).having(sum: 10) # SELECT * FROM items GROUP BY sum HAVING (sum = 10)
Source
# File lib/sequel/dataset/query.rb 455 def intersect(dataset, opts=OPTS) 456 raise(InvalidOperation, "INTERSECT not supported") unless supports_intersect_except? 457 raise(InvalidOperation, "INTERSECT ALL not supported") if opts[:all] && !supports_intersect_except_all? 458 compound_clone(:intersect, dataset, opts) 459 end
Adds an INTERSECT clause using a second dataset object. An INTERSECT compound dataset returns all rows in both the current dataset and the given dataset. Raises an InvalidOperation
if the operation is not supported. Options:
- :alias
-
Use the given value as the
from_self
alias - :all
-
Set to true to use INTERSECT ALL instead of INTERSECT, so duplicate rows can occur
- :from_self
-
Set to false to not wrap the returned dataset in a
from_self
, use with care.
DB[:items].intersect(DB[:other_items]) # SELECT * FROM (SELECT * FROM items INTERSECT SELECT * FROM other_items) AS t1 DB[:items].intersect(DB[:other_items], all: true, from_self: false) # SELECT * FROM items INTERSECT ALL SELECT * FROM other_items DB[:items].intersect(DB[:other_items], alias: :i) # SELECT * FROM (SELECT * FROM items INTERSECT SELECT * FROM other_items) AS i
Source
# File lib/sequel/dataset/query.rb 472 def invert 473 cached_dataset(:_invert_ds) do 474 having, where = @opts.values_at(:having, :where) 475 if having.nil? && where.nil? 476 where(false) 477 else 478 o = {} 479 o[:having] = SQL::BooleanExpression.invert(having) if having 480 o[:where] = SQL::BooleanExpression.invert(where) if where 481 clone(o) 482 end 483 end 484 end
Inverts the current WHERE and HAVING clauses. If there is neither a WHERE or HAVING clause, adds a WHERE clause that is always false.
DB[:items].where(category: 'software').invert # SELECT * FROM items WHERE (category != 'software') DB[:items].where(category: 'software', id: 3).invert # SELECT * FROM items WHERE ((category != 'software') OR (id != 3))
See documentation for exclude for how inversion is handled in regards to SQL
3-valued boolean logic.
Source
# File lib/sequel/dataset/query.rb 487 def join(*args, &block) 488 inner_join(*args, &block) 489 end
Alias of inner_join
Source
# File lib/sequel/dataset/query.rb 551 def join_table(type, table, expr=nil, options=OPTS, &block) 552 if hoist_cte?(table) 553 s, ds = hoist_cte(table) 554 return s.join_table(type, ds, expr, options, &block) 555 end 556 557 using_join = options[:join_using] || (expr.is_a?(Array) && !expr.empty? && expr.all?{|x| x.is_a?(Symbol)}) 558 if using_join && !supports_join_using? 559 h = {} 560 expr.each{|e| h[e] = e} 561 return join_table(type, table, h, options) 562 end 563 564 table_alias = options[:table_alias] 565 566 if table.is_a?(SQL::AliasedExpression) 567 table_expr = if table_alias 568 SQL::AliasedExpression.new(table.expression, table_alias, table.columns) 569 else 570 table 571 end 572 table = table_expr.expression 573 table_name = table_alias = table_expr.alias 574 elsif table.is_a?(Dataset) 575 if table_alias.nil? 576 table_alias_num = (@opts[:num_dataset_sources] || 0) + 1 577 table_alias = dataset_alias(table_alias_num) 578 end 579 table_name = table_alias 580 table_expr = SQL::AliasedExpression.new(table, table_alias) 581 else 582 table, implicit_table_alias = split_alias(table) 583 table_alias ||= implicit_table_alias 584 table_name = table_alias || table 585 table_expr = table_alias ? SQL::AliasedExpression.new(table, table_alias) : table 586 end 587 588 join = if expr.nil? and !block 589 SQL::JoinClause.new(type, table_expr) 590 elsif using_join 591 raise(Sequel::Error, "can't use a block if providing an array of symbols as expr") if block 592 SQL::JoinUsingClause.new(expr, type, table_expr) 593 else 594 last_alias = options[:implicit_qualifier] || @opts[:last_joined_table] || first_source_alias 595 qualify_type = options[:qualify] 596 if Sequel.condition_specifier?(expr) 597 expr = expr.map do |k, v| 598 qualify_type = default_join_table_qualification if qualify_type.nil? 599 case qualify_type 600 when false 601 nil # Do no qualification 602 when :deep 603 k = Sequel::Qualifier.new(table_name).transform(k) 604 v = Sequel::Qualifier.new(last_alias).transform(v) 605 else 606 k = qualified_column_name(k, table_name) if k.is_a?(Symbol) 607 v = qualified_column_name(v, last_alias) if v.is_a?(Symbol) 608 end 609 [k,v] 610 end 611 expr = SQL::BooleanExpression.from_value_pairs(expr) 612 end 613 if block 614 expr2 = yield(table_name, last_alias, @opts[:join] || EMPTY_ARRAY) 615 expr = expr ? SQL::BooleanExpression.new(:AND, expr, expr2) : expr2 616 end 617 SQL::JoinOnClause.new(expr, type, table_expr) 618 end 619 620 opts = {:join => ((@opts[:join] || EMPTY_ARRAY) + [join]).freeze} 621 opts[:last_joined_table] = table_name unless options[:reset_implicit_qualifier] == false 622 opts[:num_dataset_sources] = table_alias_num if table_alias_num 623 clone(opts) 624 end
Returns a joined dataset. Not usually called directly, users should use the appropriate join method (e.g. join, left_join, natural_join, cross_join) which fills in the type
argument.
Takes the following arguments:
- type
-
The type of join to do (e.g. :inner)
- table
-
table to join into the current dataset. Generally one of the following types:
String
,Symbol
-
identifier used as table or view name
Dataset
-
a subselect is performed with an alias of tN for some value of N
SQL::Function
-
set returning function
SQL::AliasedExpression
-
already aliased expression. Uses given alias unless overridden by the :table_alias option.
- expr
-
conditions used when joining, depends on type:
Hash
,Array
of pairs-
Assumes key (1st arg) is column of joined table (unless already qualified), and value (2nd arg) is column of the last joined or primary table (or the :implicit_qualifier option). To specify multiple conditions on a single joined table column, you must use an array. Uses a JOIN with an ON clause.
Array
-
If all members of the array are symbols, considers them as columns and uses a JOIN with a USING clause. Most databases will remove duplicate columns from the result set if this is used.
- nil
-
If a block is not given, doesn’t use ON or USING, so the JOIN should be a NATURAL or CROSS join. If a block is given, uses an ON clause based on the block, see below.
- otherwise
-
Treats the argument as a filter expression, so strings are considered literal, symbols specify boolean columns, and
Sequel
expressions can be used. Uses a JOIN with an ON clause.
- options
-
a hash of options, with the following keys supported:
- :table_alias
-
Override the table alias used when joining. In general you shouldn’t use this option, you should provide the appropriate
SQL::AliasedExpression
as the table argument. - :implicit_qualifier
-
The name to use for qualifying implicit conditions. By default, the last joined or primary table is used.
- :join_using
-
Force the using of JOIN USING, even if
expr
is not an array of symbols. - :reset_implicit_qualifier
-
Can set to false to ignore this join when future joins determine qualifier for implicit conditions.
- :qualify
-
Can be set to false to not do any implicit qualification. Can be set to :deep to use the
Qualifier
AST Transformer, which will attempt to qualify subexpressions of the expression tree. Can be set to :symbol to only qualify symbols. Defaults to the value of default_join_table_qualification.
- block
-
The block argument should only be given if a JOIN with an ON clause is used, in which case it yields the table alias/name for the table currently being joined, the table alias/name for the last joined (or first table), and an array of previous
SQL::JoinClause
. Unlikewhere
, this block is not treated as a virtual row block.
Examples:
DB[:a].join_table(:cross, :b) # SELECT * FROM a CROSS JOIN b DB[:a].join_table(:inner, DB[:b], c: d) # SELECT * FROM a INNER JOIN (SELECT * FROM b) AS t1 ON (t1.c = a.d) DB[:a].join_table(:left, Sequel[:b].as(:c), [:d]) # SELECT * FROM a LEFT JOIN b AS c USING (d) DB[:a].natural_join(:b).join_table(:inner, :c) do |ta, jta, js| (Sequel.qualify(ta, :d) > Sequel.qualify(jta, :e)) & {Sequel.qualify(ta, :f)=>DB.from(js.first.table).select(:g)} end # SELECT * FROM a NATURAL JOIN b INNER JOIN c # ON ((c.d > b.e) AND (c.f IN (SELECT g FROM b)))
Source
# File lib/sequel/dataset/query.rb 645 def lateral 646 return self if opts[:lateral] 647 cached_dataset(:_lateral_ds){clone(:lateral=>true)} 648 end
Marks this dataset as a lateral dataset. If used in another dataset’s FROM or JOIN clauses, it will surround the subquery with LATERAL to enable it to deal with previous tables in the query:
DB.from(:a, DB[:b].where(Sequel[:a][:c]=>Sequel[:b][:d]).lateral) # SELECT * FROM a, LATERAL (SELECT * FROM b WHERE (a.c = b.d))
Source
# File lib/sequel/dataset/query.rb 660 def limit(l, o = (no_offset = true; nil)) 661 return from_self.limit(l, o) if @opts[:sql] 662 663 if l.is_a?(Range) 664 no_offset = false 665 o = l.first 666 l = l.last - l.first + (l.exclude_end? ? 0 : 1) 667 end 668 l = l.to_i if l.is_a?(String) && !l.is_a?(LiteralString) 669 if l.is_a?(Integer) 670 raise(Error, 'Limits must be greater than or equal to 1') unless l >= 1 671 end 672 673 ds = clone(:limit=>l) 674 ds = ds.offset(o) unless no_offset 675 ds 676 end
If given an integer, the dataset will contain only the first l results. If given a range, it will contain only those at offsets within that range. If a second argument is given, it is used as an offset. To use an offset without a limit, pass nil as the first argument.
DB[:items].limit(10) # SELECT * FROM items LIMIT 10 DB[:items].limit(10, 20) # SELECT * FROM items LIMIT 10 OFFSET 20 DB[:items].limit(10...20) # SELECT * FROM items LIMIT 10 OFFSET 10 DB[:items].limit(10..20) # SELECT * FROM items LIMIT 11 OFFSET 10 DB[:items].limit(nil, 20) # SELECT * FROM items OFFSET 20
Source
# File lib/sequel/dataset/query.rb 690 def lock_style(style) 691 clone(:lock => style) 692 end
Returns a cloned dataset with the given lock style. If style is a string, it will be used directly. You should never pass a string to this method that is derived from user input, as that can lead to SQL
injection.
A symbol may be used for database independent locking behavior, but all supported symbols have separate methods (e.g. for_update
).
DB[:items].lock_style('FOR SHARE NOWAIT') # SELECT * FROM items FOR SHARE NOWAIT DB[:items].lock_style('FOR UPDATE OF table1 SKIP LOCKED') # SELECT * FROM items FOR UPDATE OF table1 SKIP LOCKED
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# File lib/sequel/dataset/query.rb 703 def merge_delete(&block) 704 _merge_when(:type=>:delete, &block) 705 end
Return a dataset with a WHEN MATCHED THEN DELETE clause added to the MERGE statement. If a block is passed, treat it as a virtual row and use it as additional conditions for the match.
merge_delete # WHEN MATCHED THEN DELETE merge_delete{a > 30} # WHEN MATCHED AND (a > 30) THEN DELETE
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# File lib/sequel/dataset/query.rb 719 def merge_insert(*values, &block) 720 _merge_when(:type=>:insert, :values=>values, &block) 721 end
Return a dataset with a WHEN NOT MATCHED THEN INSERT clause added to the MERGE statement. If a block is passed, treat it as a virtual row and use it as additional conditions for the match.
The arguments provided can be any arguments that would be accepted by insert
.
merge_insert(i1: :i2, a: Sequel[:b]+11) # WHEN NOT MATCHED THEN INSERT (i1, a) VALUES (i2, (b + 11)) merge_insert(:i2, Sequel[:b]+11){a > 30} # WHEN NOT MATCHED AND (a > 30) THEN INSERT VALUES (i2, (b + 11))
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# File lib/sequel/dataset/query.rb 732 def merge_update(values, &block) 733 _merge_when(:type=>:update, :values=>values, &block) 734 end
Return a dataset with a WHEN MATCHED THEN UPDATE clause added to the MERGE statement. If a block is passed, treat it as a virtual row and use it as additional conditions for the match.
merge_update(i1: Sequel[:i1]+:i2+10, a: Sequel[:a]+:b+20) # WHEN MATCHED THEN UPDATE SET i1 = (i1 + i2 + 10), a = (a + b + 20) merge_update(i1: :i2){a > 30} # WHEN MATCHED AND (a > 30) THEN UPDATE SET i1 = i2
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# File lib/sequel/dataset/query.rb 740 def merge_using(source, join_condition) 741 clone(:merge_using => [source, join_condition].freeze) 742 end
Return a dataset with the source and join condition to use for the MERGE statement.
merge_using(:m2, i1: :i2) # USING m2 ON (i1 = i2)
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# File lib/sequel/dataset/query.rb 749 def naked 750 return self unless opts[:row_proc] 751 cached_dataset(:_naked_ds){with_row_proc(nil)} 752 end
Returns a cloned dataset without a row_proc.
ds = DB[:items].with_row_proc(:invert.to_proc) ds.all # => [{2=>:id}] ds.naked.all # => [{:id=>2}]
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# File lib/sequel/dataset/query.rb 759 def nowait 760 return self if opts[:nowait] 761 cached_dataset(:_nowait_ds) do 762 raise(Error, 'This dataset does not support raises errors instead of waiting for locked rows') unless supports_nowait? 763 clone(:nowait=>true) 764 end 765 end
Returns a copy of the dataset that will raise a DatabaseLockTimeout instead of waiting for rows that are locked by another transaction
DB[:items].for_update.nowait # SELECT * FROM items FOR UPDATE NOWAIT
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# File lib/sequel/dataset/query.rb 772 def offset(o) 773 o = o.to_i if o.is_a?(String) && !o.is_a?(LiteralString) 774 if o.is_a?(Integer) 775 raise(Error, 'Offsets must be greater than or equal to 0') unless o >= 0 776 end 777 clone(:offset => o) 778 end
Returns a copy of the dataset with a specified order. Can be safely combined with limit. If you call limit with an offset, it will override the offset if you’ve called offset first.
DB[:items].offset(10) # SELECT * FROM items OFFSET 10
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# File lib/sequel/dataset/query.rb 786 def or(*cond, &block) 787 if @opts[:where].nil? 788 self 789 else 790 add_filter(:where, cond, false, :OR, &block) 791 end 792 end
Adds an alternate filter to an existing WHERE clause using OR. If there is no WHERE clause, then the default is WHERE true, and OR would be redundant, so return the dataset in that case.
DB[:items].where(:a).or(:b) # SELECT * FROM items WHERE a OR b DB[:items].or(:b) # SELECT * FROM items
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# File lib/sequel/dataset/query.rb 808 def order(*columns, &block) 809 virtual_row_columns(columns, block) 810 clone(:order => (columns.compact.empty?) ? nil : columns.freeze) 811 end
Returns a copy of the dataset with the order changed. If the dataset has an existing order, it is ignored and overwritten with this order. If a nil is given the returned dataset has no order. This can accept multiple arguments of varying kinds, such as SQL
functions. If a block is given, it is treated as a virtual row block, similar to where
.
DB[:items].order(:name) # SELECT * FROM items ORDER BY name DB[:items].order(:a, :b) # SELECT * FROM items ORDER BY a, b DB[:items].order(Sequel.lit('a + b')) # SELECT * FROM items ORDER BY a + b DB[:items].order(Sequel[:a] + :b) # SELECT * FROM items ORDER BY (a + b) DB[:items].order(Sequel.desc(:name)) # SELECT * FROM items ORDER BY name DESC DB[:items].order(Sequel.asc(:name, nulls: :last)) # SELECT * FROM items ORDER BY name ASC NULLS LAST DB[:items].order{sum(name).desc} # SELECT * FROM items ORDER BY sum(name) DESC DB[:items].order(nil) # SELECT * FROM items
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# File lib/sequel/dataset/query.rb 818 def order_append(*columns, &block) 819 columns = @opts[:order] + columns if @opts[:order] 820 order(*columns, &block) 821 end
Returns a copy of the dataset with the order columns added to the end of the existing order.
DB[:items].order(:a).order(:b) # SELECT * FROM items ORDER BY b DB[:items].order(:a).order_append(:b) # SELECT * FROM items ORDER BY a, b
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# File lib/sequel/dataset/query.rb 824 def order_by(*columns, &block) 825 order(*columns, &block) 826 end
Alias of order
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# File lib/sequel/dataset/query.rb 829 def order_more(*columns, &block) 830 order_append(*columns, &block) 831 end
Alias of order_append.
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# File lib/sequel/dataset/query.rb 838 def order_prepend(*columns, &block) 839 ds = order(*columns, &block) 840 @opts[:order] ? ds.order_append(*@opts[:order]) : ds 841 end
Returns a copy of the dataset with the order columns added to the beginning of the existing order.
DB[:items].order(:a).order(:b) # SELECT * FROM items ORDER BY b DB[:items].order(:a).order_prepend(:b) # SELECT * FROM items ORDER BY b, a
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# File lib/sequel/dataset/query.rb 850 def qualify(table=(cache=true; first_source)) 851 o = @opts 852 return self if o[:sql] 853 854 pr = proc do 855 h = {} 856 (o.keys & QUALIFY_KEYS).each do |k| 857 h[k] = qualified_expression(o[k], table) 858 end 859 h[:select] = [SQL::ColumnAll.new(table)].freeze if !o[:select] || o[:select].empty? 860 clone(h) 861 end 862 863 cache ? cached_dataset(:_qualify_ds, &pr) : pr.call 864 end
Qualify to the given table, or first source if no table is given.
DB[:items].where(id: 1).qualify # SELECT items.* FROM items WHERE (items.id = 1) DB[:items].where(id: 1).qualify(:i) # SELECT i.* FROM items WHERE (i.id = 1)
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# File lib/sequel/dataset/query.rb 884 def returning(*values) 885 if values.empty? 886 return self if opts[:returning] == EMPTY_ARRAY 887 cached_dataset(:_returning_ds) do 888 raise Error, "RETURNING is not supported on #{db.database_type}" unless supports_returning?(:insert) 889 clone(:returning=>EMPTY_ARRAY) 890 end 891 else 892 raise Error, "RETURNING is not supported on #{db.database_type}" unless supports_returning?(:insert) 893 clone(:returning=>values.freeze) 894 end 895 end
Modify the RETURNING clause, only supported on a few databases. If returning is used, instead of insert returning the autogenerated primary key or update/delete returning the number of modified rows, results are returned using fetch_rows
.
DB[:items].returning # RETURNING * DB[:items].returning(nil) # RETURNING NULL DB[:items].returning(:id, :name) # RETURNING id, name DB[:items].returning.insert(a: 1) do |hash| # hash for each row inserted, with values for all columns end DB[:items].returning.update(a: 1) do |hash| # hash for each row updated, with values for all columns end DB[:items].returning.delete(a: 1) do |hash| # hash for each row deleted, with values for all columns end
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# File lib/sequel/dataset/query.rb 904 def reverse(*order, &block) 905 if order.empty? && !block 906 cached_dataset(:_reverse_ds){order(*invert_order(@opts[:order]))} 907 else 908 virtual_row_columns(order, block) 909 order(*invert_order(order.empty? ? @opts[:order] : order.freeze)) 910 end 911 end
Returns a copy of the dataset with the order reversed. If no order is given, the existing order is inverted.
DB[:items].reverse(:id) # SELECT * FROM items ORDER BY id DESC DB[:items].reverse{foo(bar)} # SELECT * FROM items ORDER BY foo(bar) DESC DB[:items].order(:id).reverse # SELECT * FROM items ORDER BY id DESC DB[:items].order(:id).reverse(Sequel.desc(:name)) # SELECT * FROM items ORDER BY name ASC
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# File lib/sequel/dataset/query.rb 914 def reverse_order(*order, &block) 915 reverse(*order, &block) 916 end
Alias of reverse
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# File lib/sequel/dataset/query.rb 925 def select(*columns, &block) 926 virtual_row_columns(columns, block) 927 clone(:select => columns.freeze) 928 end
Returns a copy of the dataset with the columns selected changed to the given columns. This also takes a virtual row block, similar to where
.
DB[:items].select(:a) # SELECT a FROM items DB[:items].select(:a, :b) # SELECT a, b FROM items DB[:items].select{[a, sum(b)]} # SELECT a, sum(b) FROM items
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# File lib/sequel/dataset/query.rb 937 def select_all(*tables) 938 if tables.empty? 939 return self unless opts[:select] 940 cached_dataset(:_select_all_ds){clone(:select => nil)} 941 else 942 select(*tables.map{|t| i, a = split_alias(t); a || i}.map!{|t| SQL::ColumnAll.new(t)}.freeze) 943 end 944 end
Returns a copy of the dataset selecting the wildcard if no arguments are given. If arguments are given, treat them as tables and select all columns (using the wildcard) from each table.
DB[:items].select(:a).select_all # SELECT * FROM items DB[:items].select_all(:items) # SELECT items.* FROM items DB[:items].select_all(:items, :foo) # SELECT items.*, foo.* FROM items
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# File lib/sequel/dataset/query.rb 953 def select_append(*columns, &block) 954 virtual_row_columns(columns, block) 955 select(*(_current_select(true) + columns)) 956 end
Returns a copy of the dataset with the given columns added to the existing selected columns. If no columns are currently selected, it will select the columns given in addition to *.
DB[:items].select(:a).select(:b) # SELECT b FROM items DB[:items].select(:a).select_append(:b) # SELECT a, b FROM items DB[:items].select_append(:b) # SELECT *, b FROM items
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# File lib/sequel/dataset/query.rb 967 def select_group(*columns, &block) 968 virtual_row_columns(columns, block) 969 select(*columns).group(*columns.map{|c| unaliased_identifier(c)}) 970 end
Set both the select and group clauses with the given columns
. Column aliases may be supplied, and will be included in the select clause. This also takes a virtual row block similar to where
.
DB[:items].select_group(:a, :b) # SELECT a, b FROM items GROUP BY a, b DB[:items].select_group(Sequel[:c].as(:a)){f(c2)} # SELECT c AS a, f(c2) FROM items GROUP BY c, f(c2)
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# File lib/sequel/dataset/query.rb 973 def select_more(*columns, &block) 974 select_append(*columns, &block) 975 end
Alias for select_append.
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# File lib/sequel/dataset/query.rb 984 def select_prepend(*columns, &block) 985 virtual_row_columns(columns, block) 986 select(*(columns + _current_select(false))) 987 end
Returns a copy of the dataset with the given columns added to the existing selected columns. If no columns are currently selected, it will select the columns given in addition to *.
DB[:items].select(:a).select(:b) # SELECT b FROM items DB[:items].select(:a).select_prepend(:b) # SELECT b, a FROM items DB[:items].select_prepend(:b) # SELECT b, * FROM items
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# File lib/sequel/dataset/query.rb 998 def server(servr) 999 clone(:server=>servr) 1000 end
Set the server for this dataset to use. Used to pick a specific database shard to run a query against, or to override the default (where SELECT uses :read_only database and all other queries use the :default database). This method is always available but is only useful when database sharding is being used.
DB[:items].all # Uses the :read_only or :default server DB[:items].delete # Uses the :default server DB[:items].server(:blah).delete # Uses the :blah server
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# File lib/sequel/dataset/query.rb 1005 def server?(server) 1006 if db.sharded? && !opts[:server] 1007 server(server) 1008 else 1009 self 1010 end 1011 end
If the database uses sharding and the current dataset has not had a server set, return a cloned dataset that uses the given server. Otherwise, return the receiver directly instead of returning a clone.
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# File lib/sequel/dataset/query.rb 1014 def skip_limit_check 1015 return self if opts[:skip_limit_check] 1016 cached_dataset(:_skip_limit_check_ds) do 1017 clone(:skip_limit_check=>true) 1018 end 1019 end
Specify that the check for limits/offsets when updating/deleting be skipped for the dataset.
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# File lib/sequel/dataset/query.rb 1022 def skip_locked 1023 return self if opts[:skip_locked] 1024 cached_dataset(:_skip_locked_ds) do 1025 raise(Error, 'This dataset does not support skipping locked rows') unless supports_skip_locked? 1026 clone(:skip_locked=>true) 1027 end 1028 end
Skip locked rows when returning results from this dataset.
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# File lib/sequel/dataset/query.rb 1034 def unfiltered 1035 return self unless opts[:where] || opts[:having] 1036 cached_dataset(:_unfiltered_ds){clone(:where => nil, :having => nil)} 1037 end
Returns a copy of the dataset with no filters (HAVING or WHERE clause) applied.
DB[:items].group(:a).having(a: 1).where(:b).unfiltered # SELECT * FROM items GROUP BY a
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# File lib/sequel/dataset/query.rb 1043 def ungrouped 1044 return self unless opts[:group] || opts[:having] 1045 cached_dataset(:_ungrouped_ds){clone(:group => nil, :having => nil)} 1046 end
Returns a copy of the dataset with no grouping (GROUP or HAVING clause) applied.
DB[:items].group(:a).having(a: 1).where(:b).ungrouped # SELECT * FROM items WHERE b
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# File lib/sequel/dataset/query.rb 1064 def union(dataset, opts=OPTS) 1065 compound_clone(:union, dataset, opts) 1066 end
Adds a UNION clause using a second dataset object. A UNION compound dataset returns all rows in either the current dataset or the given dataset. Options:
- :alias
-
Use the given value as the
from_self
alias - :all
-
Set to true to use UNION ALL instead of UNION, so duplicate rows can occur
- :from_self
-
Set to false to not wrap the returned dataset in a
from_self
, use with care.
DB[:items].union(DB[:other_items]) # SELECT * FROM (SELECT * FROM items UNION SELECT * FROM other_items) AS t1 DB[:items].union(DB[:other_items], all: true, from_self: false) # SELECT * FROM items UNION ALL SELECT * FROM other_items DB[:items].union(DB[:other_items], alias: :i) # SELECT * FROM (SELECT * FROM items UNION SELECT * FROM other_items) AS i
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# File lib/sequel/dataset/query.rb 1071 def unlimited 1072 return self unless opts[:limit] || opts[:offset] 1073 cached_dataset(:_unlimited_ds){clone(:limit=>nil, :offset=>nil)} 1074 end
Returns a copy of the dataset with no limit or offset.
DB[:items].limit(10, 20).unlimited # SELECT * FROM items
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# File lib/sequel/dataset/query.rb 1079 def unordered 1080 return self unless opts[:order] 1081 cached_dataset(:_unordered_ds){clone(:order=>nil)} 1082 end
Returns a copy of the dataset with no order.
DB[:items].order(:a).unordered # SELECT * FROM items
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# File lib/sequel/dataset/query.rb 1126 def where(*cond, &block) 1127 add_filter(:where, cond, &block) 1128 end
Returns a copy of the dataset with the given WHERE conditions imposed upon it.
Accepts the following argument types:
Hash
,Array
of pairs-
list of equality/inclusion expressions
Symbol
-
taken as a boolean column argument (e.g. WHERE active)
Sequel::SQL::BooleanExpression
,Sequel::LiteralString
-
an existing condition expression, probably created using the
Sequel
expression filter DSL.
where also accepts a block, which should return one of the above argument types, and is treated the same way. This block yields a virtual row object, which is easy to use to create identifiers and functions. For more details on the virtual row support, see the “Virtual Rows” guide
If both a block and regular argument are provided, they get ANDed together.
Examples:
DB[:items].where(id: 3) # SELECT * FROM items WHERE (id = 3) DB[:items].where(Sequel.lit('price < ?', 100)) # SELECT * FROM items WHERE price < 100 DB[:items].where([[:id, [1,2,3]], [:id, 0..10]]) # SELECT * FROM items WHERE ((id IN (1, 2, 3)) AND ((id >= 0) AND (id <= 10))) DB[:items].where(Sequel.lit('price < 100')) # SELECT * FROM items WHERE price < 100 DB[:items].where(:active) # SELECT * FROM items WHERE :active DB[:items].where{price < 100} # SELECT * FROM items WHERE (price < 100)
Multiple where calls can be chained for scoping:
software = dataset.where(category: 'software').where{price < 100} # SELECT * FROM items WHERE ((category = 'software') AND (price < 100))
See the “Dataset Filtering” guide for more examples and details.
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# File lib/sequel/dataset/query.rb 1136 def window(name, opts) 1137 clone(:window=>((@opts[:window]||EMPTY_ARRAY) + [[name, SQL::Window.new(opts)].freeze]).freeze) 1138 end
Return a clone of the dataset with an addition named window that can be referenced in window functions. See Sequel::SQL::Window
for a list of options that can be passed in. Example:
DB[:items].window(:w, partition: :c1, order: :c2) # SELECT * FROM items WINDOW w AS (PARTITION BY c1 ORDER BY c2)
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# File lib/sequel/dataset/query.rb 1151 def with(name, dataset, opts=OPTS) 1152 raise(Error, 'This dataset does not support common table expressions') unless supports_cte? 1153 if hoist_cte?(dataset) 1154 s, ds = hoist_cte(dataset) 1155 s.with(name, ds, opts) 1156 else 1157 clone(:with=>((@opts[:with]||EMPTY_ARRAY) + [Hash[opts].merge!(:name=>name, :dataset=>dataset)]).freeze) 1158 end 1159 end
Add a common table expression (CTE) with the given name and a dataset that defines the CTE. A common table expression acts as an inline view for the query.
Options:
- :args
-
Specify the arguments/columns for the CTE, should be an array of symbols.
- :recursive
-
Specify that this is a recursive CTE
- :materialized
-
Set to false to force inlining of the CTE, or true to force not inlining the CTE (PostgreSQL 12+/SQLite 3.35+).
DB[:items].with(:items, DB[:syx].where(Sequel[:name].like('A%'))) # WITH items AS (SELECT * FROM syx WHERE (name LIKE 'A%' ESCAPE '\')) SELECT * FROM items
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# File lib/sequel/dataset/query.rb 1240 def with_extend(*mods, &block) 1241 c = Class.new(self.class) 1242 c.include(*mods) unless mods.empty? 1243 c.include(DatasetModule.new(&block)) if block 1244 o = c.freeze.allocate 1245 o.instance_variable_set(:@db, @db) 1246 o.instance_variable_set(:@opts, @opts) 1247 o.instance_variable_set(:@cache, {}) 1248 if cols = cache_get(:_columns) 1249 o.send(:columns=, cols) 1250 end 1251 o.freeze 1252 end
Create a subclass of the receiver’s class, and include the given modules into it. If a block is provided, a DatasetModule
is created using the block and is included into the subclass. Create an instance of the subclass using the same db and opts, so that the returned dataset operates similarly to a clone extended with the given modules. This approach is used to avoid singleton classes, which significantly improves performance.
Note that like Object#extend, when multiple modules are provided as arguments the subclass includes the modules in reverse order.
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# File lib/sequel/dataset/query.rb 1217 def with_recursive(name, nonrecursive, recursive, opts=OPTS) 1218 raise(Error, 'This dataset does not support common table expressions') unless supports_cte? 1219 if hoist_cte?(nonrecursive) 1220 s, ds = hoist_cte(nonrecursive) 1221 s.with_recursive(name, ds, recursive, opts) 1222 elsif hoist_cte?(recursive) 1223 s, ds = hoist_cte(recursive) 1224 s.with_recursive(name, nonrecursive, ds, opts) 1225 else 1226 clone(:with=>((@opts[:with]||EMPTY_ARRAY) + [Hash[opts].merge!(:recursive=>true, :name=>name, :dataset=>nonrecursive.union(recursive, {:all=>opts[:union_all] != false, :from_self=>false}))]).freeze) 1227 end 1228 end
Add a recursive common table expression (CTE) with the given name, a dataset that defines the nonrecursive part of the CTE, and a dataset that defines the recursive part of the CTE.
Options:
- :args
-
Specify the arguments/columns for the CTE, should be an array of symbols.
- :union_all
-
Set to false to use UNION instead of UNION ALL combining the nonrecursive and recursive parts.
PostgreSQL 14+ Options:
- :cycle
-
Stop recursive searching when a cycle is detected. Includes two columns in the result of the CTE, a cycle column indicating whether a cycle was detected for the current row, and a path column for the path traversed to get to the current row. If given, must be a hash with the following keys:
- :columns
-
(required) The column or array of columns to use to detect a cycle. If the value of these columns match columns already traversed, then a cycle is detected, and recursive searching will not traverse beyond the cycle (the CTE will include the row where the cycle was detected).
- :cycle_column
-
The name of the cycle column in the output, defaults to :is_cycle.
- :cycle_value
-
The value of the cycle column in the output if the current row was detected as a cycle, defaults to true.
- :noncycle_value
-
The value of the cycle column in the output if the current row was not detected as a cycle, defaults to false. Only respected if :cycle_value is given.
- :path_column
-
The name of the path column in the output, defaults to :path.
- :search
-
Include an order column in the result of the CTE that allows for breadth or depth first searching. If given, must be a hash with the following keys:
- :by
-
(required) The column or array of columns to search by.
- :order_column
-
The name of the order column in the output, defaults to :ordercol.
- :type
-
Set to :breadth to use breadth-first searching (depth-first searching is the default).
DB[:t].with_recursive(:t, DB[:i1].select(:id, :parent_id).where(parent_id: nil), DB[:i1].join(:t, id: :parent_id).select(Sequel[:i1][:id], Sequel[:i1][:parent_id]), args: [:id, :parent_id]) # WITH RECURSIVE t(id, parent_id) AS ( # SELECT id, parent_id FROM i1 WHERE (parent_id IS NULL) # UNION ALL # SELECT i1.id, i1.parent_id FROM i1 INNER JOIN t ON (t.id = i1.parent_id) # ) SELECT * FROM t DB[:t].with_recursive(:t, DB[:i1].where(parent_id: nil), DB[:i1].join(:t, id: :parent_id).select_all(:i1), search: {by: :id, type: :breadth}, cycle: {columns: :id, cycle_value: 1, noncycle_value: 2}) # WITH RECURSIVE t AS ( # SELECT * FROM i1 WHERE (parent_id IS NULL) # UNION ALL # (SELECT i1.* FROM i1 INNER JOIN t ON (t.id = i1.parent_id)) # ) # SEARCH BREADTH FIRST BY id SET ordercol # CYCLE id SET is_cycle TO 1 DEFAULT 2 USING path # SELECT * FROM t
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# File lib/sequel/dataset/query.rb 1269 def with_row_proc(callable) 1270 clone(:row_proc=>callable) 1271 end
Returns a cloned dataset with the given row_proc.
ds = DB[:items] ds.all # => [{:id=>2}] ds.with_row_proc(:invert.to_proc).all # => [{2=>:id}]
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# File lib/sequel/dataset/query.rb 1303 def with_sql(sql, *args) 1304 if sql.is_a?(Symbol) 1305 sql = public_send(sql, *args) 1306 else 1307 sql = SQL::PlaceholderLiteralString.new(sql, args) unless args.empty? 1308 end 1309 clone(:sql=>sql) 1310 end
Returns a copy of the dataset with the static SQL
used. This is useful if you want to keep the same row_proc/graph, but change the SQL
used to custom SQL
.
DB[:items].with_sql('SELECT * FROM foo') # SELECT * FROM foo
You can use placeholders in your SQL
and provide arguments for those placeholders:
DB[:items].with_sql('SELECT ? FROM foo', 1) # SELECT 1 FROM foo
You can also provide a method name and arguments to call to get the SQL:
DB[:items].with_sql(:insert_sql, b: 1) # INSERT INTO items (b) VALUES (1)
Note that datasets that specify custom SQL
using this method will generally ignore future dataset methods that modify the SQL
used, as specifying custom SQL
overrides Sequel’s SQL
generator. You should probably limit yourself to the following dataset methods when using this method, or use the implicit_subquery extension:
-
each
-
all
-
single_record
(if only one record could be returned) -
single_value
(if only one record could be returned, and a single column is selected) -
map
-
delete (if a DELETE statement)
-
update (if an UPDATE statement, with no arguments)
-
insert (if an INSERT statement, with no arguments)
-
truncate (if a TRUNCATE statement, with no arguments)
Protected Instance Methods
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# File lib/sequel/dataset/query.rb 1315 def compound_clone(type, dataset, opts) 1316 if dataset.is_a?(Dataset) && dataset.opts[:with] && !supports_cte_in_compounds? 1317 s, ds = hoist_cte(dataset) 1318 return s.compound_clone(type, ds, opts) 1319 end 1320 ds = compound_from_self.clone(:compounds=>(Array(@opts[:compounds]).map(&:dup) + [[type, dataset.compound_from_self, opts[:all]].freeze]).freeze) 1321 opts[:from_self] == false ? ds : ds.from_self(opts) 1322 end
Add the dataset to the list of compounds
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# File lib/sequel/dataset/query.rb 1325 def options_overlap(opts) 1326 !(@opts.map{|k,v| k unless v.nil?}.compact & opts).empty? 1327 end
Return true if the dataset has a non-nil value for any key in opts.
Source
# File lib/sequel/dataset/query.rb 1336 def simple_select_all? 1337 return false unless (f = @opts[:from]) && f.length == 1 1338 o = @opts.reject{|k,v| v.nil? || non_sql_option?(k)} 1339 from = f.first 1340 from = from.expression if from.is_a?(SQL::AliasedExpression) 1341 1342 if SIMPLE_SELECT_ALL_ALLOWED_FROM.any?{|x| from.is_a?(x)} 1343 case o.length 1344 when 1 1345 true 1346 when 2 1347 (s = o[:select]) && s.length == 1 && s.first.is_a?(SQL::ColumnAll) 1348 else 1349 false 1350 end 1351 else 1352 false 1353 end 1354 end
Whether this dataset is a simple select from an underlying table, such as:
SELECT * FROM table SELECT table.* FROM table
Private Instance Methods
Source
# File lib/sequel/dataset/query.rb 1376 def _current_select(allow_plain_wildcard) 1377 cur_sel = @opts[:select] 1378 1379 if !cur_sel || cur_sel.empty? 1380 cur_sel = if allow_plain_wildcard && supports_select_all_and_column? 1381 [WILDCARD].freeze 1382 else 1383 _current_select_column_all 1384 end 1385 elsif !allow_plain_wildcard && cur_sel.include?(WILDCARD) 1386 cur_sel = cur_sel.dup 1387 index = cur_sel.index(WILDCARD) 1388 cur_sel.delete(WILDCARD) 1389 _current_select_column_all.each_with_index do |ca, i| 1390 cur_sel.insert(index+i, ca) 1391 end 1392 cur_sel.freeze 1393 end 1394 1395 cur_sel 1396 end
A frozen array for the currently selected columns.
Source
# File lib/sequel/dataset/query.rb 1400 def _current_select_column_all 1401 tables = Array(@opts[:from]) + Array(@opts[:join]) 1402 tables.map{|t| i, a = split_alias(t); a || i}.map!{|t| SQL::ColumnAll.new(t)}.freeze 1403 end
An array of SQL::ColumnAll
objects for all FROM and JOIN tables. Used for select_append
and select_prepend.
Source
# File lib/sequel/dataset/query.rb 1361 def _extension!(exts) 1362 Sequel.extension(*exts) 1363 exts.each do |ext| 1364 if pr = Sequel.synchronize{EXTENSIONS[ext]} 1365 pr.call(self) 1366 else 1367 raise(Error, "Extension #{ext} does not have specific support handling individual datasets (try: Sequel.extension #{ext.inspect})") 1368 end 1369 end 1370 self 1371 end
Load the extensions into the receiver, without checking if the receiver is frozen.
Source
# File lib/sequel/dataset/query.rb 1406 def _invert_filter(cond, invert) 1407 if invert 1408 SQL::BooleanExpression.invert(cond) 1409 else 1410 cond 1411 end 1412 end
If invert is true, invert the condition.
Source
# File lib/sequel/dataset/query.rb 1416 def _merge_when(hash, &block) 1417 hash[:conditions] = Sequel.virtual_row(&block) if block 1418 1419 if merge_when = @opts[:merge_when] 1420 clone(:merge_when => (merge_when.dup << hash.freeze).freeze) 1421 else 1422 clone(:merge_when => [hash.freeze].freeze) 1423 end 1424 end
Append to the current MERGE WHEN clauses. Mutates the hash to add the conditions, if a virtual row block is passed.
Source
# File lib/sequel/dataset/query.rb 1431 def add_filter(clause, cond, invert=false, combine=:AND, &block) 1432 if cond == EMPTY_ARRAY && !block 1433 raise Error, "must provide an argument to a filtering method if not passing a block" 1434 end 1435 1436 cond = cond.first if cond.size == 1 1437 1438 empty = cond == OPTS || cond == EMPTY_ARRAY 1439 1440 if empty && !block 1441 self 1442 else 1443 if cond == nil 1444 cond = Sequel::NULL 1445 end 1446 if empty && block 1447 cond = nil 1448 end 1449 1450 cond = _invert_filter(filter_expr(cond, &block), invert) 1451 cond = SQL::BooleanExpression.new(combine, @opts[clause], cond) if @opts[clause] 1452 1453 if cond.nil? 1454 cond = Sequel::NULL 1455 end 1456 1457 clone(clause => cond) 1458 end 1459 end
Add the given filter condition. Arguments:
Source
# File lib/sequel/dataset/query.rb 1462 def default_join_table_qualification 1463 :symbol 1464 end
The default :qualify option to use for join tables if one is not specified.
Source
# File lib/sequel/dataset/query.rb 1537 def default_server 1538 server?(:default) 1539 end
Return self if the dataset already has a server, or a cloned dataset with the default server otherwise.
Source
# File lib/sequel/dataset/query.rb 1467 def filter_expr(expr = nil, &block) 1468 expr = nil if expr == EMPTY_ARRAY 1469 1470 if block 1471 cond = filter_expr(Sequel.virtual_row(&block)) 1472 cond = SQL::BooleanExpression.new(:AND, filter_expr(expr), cond) if expr 1473 return cond 1474 end 1475 1476 case expr 1477 when Hash 1478 SQL::BooleanExpression.from_value_pairs(expr) 1479 when Array 1480 if Sequel.condition_specifier?(expr) 1481 SQL::BooleanExpression.from_value_pairs(expr) 1482 else 1483 raise Error, "Invalid filter expression: #{expr.inspect}" 1484 end 1485 when LiteralString 1486 LiteralString.new("(#{expr})") 1487 when Numeric, SQL::NumericExpression, SQL::StringExpression, Proc, String 1488 raise Error, "Invalid filter expression: #{expr.inspect}" 1489 when TrueClass, FalseClass 1490 if supports_where_true? 1491 SQL::BooleanExpression.new(:NOOP, expr) 1492 elsif expr 1493 SQL::Constants::SQLTRUE 1494 else 1495 SQL::Constants::SQLFALSE 1496 end 1497 when PlaceholderLiteralizer::Argument 1498 expr.transform{|v| filter_expr(v)} 1499 when SQL::PlaceholderLiteralString 1500 expr.with_parens 1501 else 1502 expr 1503 end 1504 end
SQL
expression object based on the expr type. See where
.
Source
# File lib/sequel/dataset/query.rb 1509 def hoist_cte(ds) 1510 [clone(:with => ((opts[:with] || EMPTY_ARRAY) + ds.opts[:with]).freeze), ds.clone(:with => nil)] 1511 end
Return two datasets, the first a clone of the receiver with the WITH clause from the given dataset added to it, and the second a clone of the given dataset with the WITH clause removed.
Source
# File lib/sequel/dataset/query.rb 1514 def hoist_cte?(ds) 1515 ds.is_a?(Dataset) && ds.opts[:with] && !supports_cte_in_subqueries? 1516 end
Whether CTEs need to be hoisted from the given ds into the current ds.
Source
# File lib/sequel/dataset/query.rb 1523 def invert_order(order) 1524 return unless order 1525 order.map do |f| 1526 case f 1527 when SQL::OrderedExpression 1528 f.invert 1529 else 1530 SQL::OrderedExpression.new(f) 1531 end 1532 end 1533 end
Inverts the given order by breaking it into a list of column references and inverting them.
DB[:items].invert_order([Sequel.desc(:id)]]) #=> [Sequel.asc(:id)] DB[:items].invert_order([:category, Sequel.desc(:price)]) #=> [Sequel.desc(:category), Sequel.asc(:price)]
Source
# File lib/sequel/dataset/query.rb 1542 def non_sql_option?(key) 1543 NON_SQL_OPTIONS.include?(key) 1544 end
Whether the given option key does not affect the generated SQL
.
Source
# File lib/sequel/dataset/query.rb 1548 def virtual_row_columns(columns, block) 1549 if block 1550 v = Sequel.virtual_row(&block) 1551 if v.is_a?(Array) 1552 columns.concat(v) 1553 else 1554 columns << v 1555 end 1556 end 1557 end
Treat the block
as a virtual_row block if not nil
and add the resulting columns to the columns
array (modifies columns
).
2 - Methods that execute code on the database
↑ topConstants
- ACTION_METHODS
-
Action methods defined by
Sequel
that execute code on the database. - COLUMNS_CLONE_OPTIONS
-
The clone options to use when retrieving columns for a dataset.
- COUNT_SELECT
- EMPTY_SELECT
Public Instance Methods
Source
# File lib/sequel/dataset/actions.rb 28 def <<(arg) 29 insert(arg) 30 self 31 end
Inserts the given argument into the database. Returns self so it can be used safely when chaining:
DB[:items] << {id: 0, name: 'Zero'} << DB[:old_items].select(:id, name)
Source
# File lib/sequel/dataset/actions.rb 37 def [](*conditions) 38 raise(Error, 'You cannot call Dataset#[] with an integer or with no arguments') if (conditions.length == 1 and conditions.first.is_a?(Integer)) or conditions.length == 0 39 first(*conditions) 40 end
Returns the first record matching the conditions. Examples:
DB[:table][id: 1] # SELECT * FROM table WHERE (id = 1) LIMIT 1 # => {:id=>1}
Source
# File lib/sequel/dataset/actions.rb 50 def all(&block) 51 _all(block){|a| each{|r| a << r}} 52 end
Returns an array with all records in the dataset. If a block is given, the array is iterated over after all items have been loaded.
DB[:table].all # SELECT * FROM table # => [{:id=>1, ...}, {:id=>2, ...}, ...] # Iterate over all rows in the table DB[:table].all{|row| p row}
Source
# File lib/sequel/dataset/actions.rb 855 def as_hash(key_column, value_column = nil, opts = OPTS) 856 h = opts[:hash] || {} 857 meth = opts[:all] ? :all : :each 858 if value_column 859 return naked.as_hash(key_column, value_column, opts) if row_proc 860 if value_column.is_a?(Array) 861 if key_column.is_a?(Array) 862 public_send(meth){|r| h[r.values_at(*key_column)] = r.values_at(*value_column)} 863 else 864 public_send(meth){|r| h[r[key_column]] = r.values_at(*value_column)} 865 end 866 else 867 if key_column.is_a?(Array) 868 public_send(meth){|r| h[r.values_at(*key_column)] = r[value_column]} 869 else 870 public_send(meth){|r| h[r[key_column]] = r[value_column]} 871 end 872 end 873 elsif key_column.is_a?(Array) 874 public_send(meth){|r| h[key_column.map{|k| r[k]}] = r} 875 else 876 public_send(meth){|r| h[r[key_column]] = r} 877 end 878 h 879 end
Returns a hash with one column used as key and another used as value. If rows have duplicate values for the key column, the latter row(s) will overwrite the value of the previous row(s). If the value_column is not given or nil, uses the entire hash as the value.
DB[:table].as_hash(:id, :name) # SELECT * FROM table # {1=>'Jim', 2=>'Bob', ...} DB[:table].as_hash(:id) # SELECT * FROM table # {1=>{:id=>1, :name=>'Jim'}, 2=>{:id=>2, :name=>'Bob'}, ...}
You can also provide an array of column names for either the key_column, the value column, or both:
DB[:table].as_hash([:id, :foo], [:name, :bar]) # SELECT * FROM table # {[1, 3]=>['Jim', 'bo'], [2, 4]=>['Bob', 'be'], ...} DB[:table].as_hash([:id, :name]) # SELECT * FROM table # {[1, 'Jim']=>{:id=>1, :name=>'Jim'}, [2, 'Bob']=>{:id=>2, :name=>'Bob'}, ...}
Options:
- :all
-
Use all instead of each to retrieve the objects
- :hash
-
The object into which the values will be placed. If this is not given, an empty hash is used. This can be used to use a hash with a default value or default proc.
Source
# File lib/sequel/dataset/actions.rb 61 def avg(arg=(no_arg = true), &block) 62 arg = Sequel.virtual_row(&block) if no_arg 63 _aggregate(:avg, arg) 64 end
Returns the average value for the given column/expression. Uses a virtual row block if no argument is given.
DB[:table].avg(:number) # SELECT avg(number) FROM table LIMIT 1 # => 3 DB[:table].avg{function(column)} # SELECT avg(function(column)) FROM table LIMIT 1 # => 1
Source
# File lib/sequel/dataset/actions.rb 75 def columns 76 _columns || columns! 77 end
Returns the columns in the result set in order as an array of symbols. If the columns are currently cached, returns the cached value. Otherwise, a SELECT query is performed to retrieve a single row in order to get the columns.
If you are looking for all columns for a single table and maybe some information about each column (e.g. database type), see Database#schema
.
DB[:table].columns # => [:id, :name]
Source
# File lib/sequel/dataset/actions.rb 84 def columns! 85 ds = clone(COLUMNS_CLONE_OPTIONS) 86 ds.each{break} 87 88 if cols = ds.cache[:_columns] 89 self.columns = cols 90 else 91 [] 92 end 93 end
Ignore any cached column information and perform a query to retrieve a row in order to get the columns.
DB[:table].columns! # => [:id, :name]
Source
# File lib/sequel/dataset/actions.rb 108 def count(arg=(no_arg=true), &block) 109 if no_arg && !block 110 cached_dataset(:_count_ds) do 111 aggregate_dataset.select(COUNT_SELECT).single_value_ds 112 end.single_value!.to_i 113 else 114 if block 115 if no_arg 116 arg = Sequel.virtual_row(&block) 117 else 118 raise Error, 'cannot provide both argument and block to Dataset#count' 119 end 120 end 121 122 _aggregate(:count, arg) 123 end 124 end
Returns the number of records in the dataset. If an argument is provided, it is used as the argument to count. If a block is provided, it is treated as a virtual row, and the result is used as the argument to count.
DB[:table].count # SELECT count(*) AS count FROM table LIMIT 1 # => 3 DB[:table].count(:column) # SELECT count(column) AS count FROM table LIMIT 1 # => 2 DB[:table].count{foo(column)} # SELECT count(foo(column)) AS count FROM table LIMIT 1 # => 1
Source
# File lib/sequel/dataset/actions.rb 142 def delete(&block) 143 sql = delete_sql 144 if uses_returning?(:delete) 145 returning_fetch_rows(sql, &block) 146 else 147 execute_dui(sql) 148 end 149 end
Deletes the records in the dataset, returning the number of records deleted.
DB[:table].delete # DELETE * FROM table # => 3
Some databases support using multiple tables in a DELETE query. This requires multiple FROM tables (JOINs can also be used). As multiple FROM tables use an implicit CROSS JOIN, you should make sure your WHERE condition uses the appropriate filters for the FROM tables:
DB.from(:a, :b).join(:c, :d=>Sequel[:b][:e]).where{{a[:f]=>b[:g], a[:id]=>c[:h]}}. delete # DELETE FROM a # USING b # INNER JOIN c ON (c.d = b.e) # WHERE ((a.f = b.g) AND (a.id = c.h))
Source
# File lib/sequel/dataset/actions.rb 160 def each 161 if rp = row_proc 162 fetch_rows(select_sql){|r| yield rp.call(r)} 163 else 164 fetch_rows(select_sql){|r| yield r} 165 end 166 self 167 end
Iterates over the records in the dataset as they are yielded from the database adapter, and returns self.
DB[:table].each{|row| p row} # SELECT * FROM table
Note that this method is not safe to use on many adapters if you are running additional queries inside the provided block. If you are running queries inside the block, you should use all
instead of each
for the outer queries, or use a separate thread or shard inside each
.
Source
# File lib/sequel/dataset/actions.rb 175 def empty? 176 cached_dataset(:_empty_ds) do 177 (@opts[:sql] ? from_self : self).single_value_ds.unordered.select(EMPTY_SELECT) 178 end.single_value!.nil? 179 end
Returns true if no records exist in the dataset, false otherwise
DB[:table].empty? # SELECT 1 AS one FROM table LIMIT 1 # => false
Source
# File lib/sequel/dataset/actions.rb 216 def first(*args, &block) 217 case args.length 218 when 0 219 unless block 220 return(@opts[:sql] ? single_record! : single_record) 221 end 222 when 1 223 arg = args[0] 224 if arg.is_a?(Integer) 225 res = if block 226 if loader = cached_placeholder_literalizer(:_first_integer_cond_loader) do |pl| 227 where(pl.arg).limit(pl.arg) 228 end 229 230 loader.all(filter_expr(&block), arg) 231 else 232 where(&block).limit(arg).all 233 end 234 else 235 if loader = cached_placeholder_literalizer(:_first_integer_loader) do |pl| 236 limit(pl.arg) 237 end 238 239 loader.all(arg) 240 else 241 limit(arg).all 242 end 243 end 244 245 return res 246 end 247 where_args = args 248 args = arg 249 end 250 251 if loader = cached_where_placeholder_literalizer(where_args||args, block, :_first_cond_loader) do |pl| 252 _single_record_ds.where(pl.arg) 253 end 254 255 loader.first(filter_expr(args, &block)) 256 else 257 _single_record_ds.where(args, &block).single_record! 258 end 259 end
Returns the first matching record if no arguments are given. If a integer argument is given, it is interpreted as a limit, and then returns all matching records up to that limit. If any other type of argument(s) is passed, it is treated as a filter and the first matching record is returned. If a block is given, it is used to filter the dataset before returning anything.
If there are no records in the dataset, returns nil (or an empty array if an integer argument is given).
Examples:
DB[:table].first # SELECT * FROM table LIMIT 1 # => {:id=>7} DB[:table].first(2) # SELECT * FROM table LIMIT 2 # => [{:id=>6}, {:id=>4}] DB[:table].first(id: 2) # SELECT * FROM table WHERE (id = 2) LIMIT 1 # => {:id=>2} DB[:table].first(Sequel.lit("id = 3")) # SELECT * FROM table WHERE (id = 3) LIMIT 1 # => {:id=>3} DB[:table].first(Sequel.lit("id = ?", 4)) # SELECT * FROM table WHERE (id = 4) LIMIT 1 # => {:id=>4} DB[:table].first{id > 2} # SELECT * FROM table WHERE (id > 2) LIMIT 1 # => {:id=>5} DB[:table].first(Sequel.lit("id > ?", 4)){id < 6} # SELECT * FROM table WHERE ((id > 4) AND (id < 6)) LIMIT 1 # => {:id=>5} DB[:table].first(2){id < 2} # SELECT * FROM table WHERE (id < 2) LIMIT 2 # => [{:id=>1}]
Source
# File lib/sequel/dataset/actions.rb 263 def first!(*args, &block) 264 first(*args, &block) || raise(Sequel::NoMatchingRow.new(self)) 265 end
Calls first. If first returns nil (signaling that no row matches), raise a Sequel::NoMatchingRow
exception.
Source
# File lib/sequel/dataset/actions.rb 291 def get(column=(no_arg=true; nil), &block) 292 ds = naked 293 if block 294 raise(Error, 'Must call Dataset#get with an argument or a block, not both') unless no_arg 295 ds = ds.select(&block) 296 column = ds.opts[:select] 297 column = nil if column.is_a?(Array) && column.length < 2 298 elsif no_arg && opts[:sql] 299 return ds.single_value! 300 else 301 case column 302 when Array 303 ds = ds.select(*column) 304 when LiteralString, Symbol, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression 305 if loader = cached_placeholder_literalizer(:_get_loader) do |pl| 306 ds.single_value_ds.select(pl.arg) 307 end 308 309 return loader.get(column) 310 end 311 312 ds = ds.select(column) 313 else 314 if loader = cached_placeholder_literalizer(:_get_alias_loader) do |pl| 315 ds.single_value_ds.select(Sequel.as(pl.arg, :v)) 316 end 317 318 return loader.get(column) 319 end 320 321 ds = ds.select(Sequel.as(column, :v)) 322 end 323 end 324 325 if column.is_a?(Array) 326 if r = ds.single_record 327 r.values_at(*hash_key_symbols(column)) 328 end 329 else 330 ds.single_value 331 end 332 end
Return the column value for the first matching record in the dataset. Raises an error if both an argument and block is given.
DB[:table].get(:id) # SELECT id FROM table LIMIT 1 # => 3 ds.get{sum(id)} # SELECT sum(id) AS v FROM table LIMIT 1 # => 6
You can pass an array of arguments to return multiple arguments, but you must make sure each element in the array has an alias that Sequel
can determine:
DB[:table].get([:id, :name]) # SELECT id, name FROM table LIMIT 1 # => [3, 'foo'] DB[:table].get{[sum(id).as(sum), name]} # SELECT sum(id) AS sum, name FROM table LIMIT 1 # => [6, 'foo']
If called on a dataset with raw SQL
, returns the first value in the dataset without changing the selection or setting a limit:
DB["SELECT id FROM table"].get # SELECT id FROM table # => 3
Source
# File lib/sequel/dataset/actions.rb 370 def import(columns, values, opts=OPTS) 371 return insert(columns, values) if values.is_a?(Dataset) 372 373 return if values.empty? 374 raise(Error, 'Using Sequel::Dataset#import with an empty column array is not allowed') if columns.empty? 375 ds = opts[:server] ? server(opts[:server]) : self 376 377 if slice_size = opts.fetch(:commit_every, opts.fetch(:slice, default_import_slice)) 378 offset = 0 379 rows = [] 380 while offset < values.length 381 rows << ds._import(columns, values[offset, slice_size], opts) 382 offset += slice_size 383 end 384 rows.flatten 385 else 386 ds._import(columns, values, opts) 387 end 388 end
Inserts multiple records into the associated table. This method can be used to efficiently insert a large number of records into a table in a single query if the database supports it. Inserts are automatically wrapped in a transaction if necessary.
This method is called with a columns array and an array of value arrays:
DB[:table].import([:x, :y], [[1, 2], [3, 4]]) # INSERT INTO table (x, y) VALUES (1, 2) # INSERT INTO table (x, y) VALUES (3, 4)
or, if the database supports it:
# INSERT INTO table (x, y) VALUES (1, 2), (3, 4)
This method also accepts a dataset instead of an array of value arrays:
DB[:table].import([:x, :y], DB[:table2].select(:a, :b)) # INSERT INTO table (x, y) SELECT a, b FROM table2
Options:
- :commit_every
-
Open a new transaction for every given number of records. For example, if you provide a value of 50, will commit after every 50 records. When a transaction is not required, this option controls the maximum number of values to insert with a single statement; it does not force the use of a transaction.
- :return
-
When this is set to :primary_key, returns an array of autoincremented primary key values for the rows inserted. This does not have an effect if
values
is aDataset
. - :server
-
Set the server/shard to use for the transaction and insert queries.
- :skip_transaction
-
Do not use a transaction even when using multiple INSERT queries.
- :slice
-
Same as :commit_every, :commit_every takes precedence.
Source
# File lib/sequel/dataset/actions.rb 426 def insert(*values, &block) 427 sql = insert_sql(*values) 428 if uses_returning?(:insert) 429 returning_fetch_rows(sql, &block) 430 else 431 execute_insert(sql) 432 end 433 end
Inserts values into the associated table. The returned value is generally the value of the autoincremented primary key for the inserted row, assuming that a single row is inserted and the table has an autoincrementing primary key.
insert
handles a number of different argument formats:
- no arguments or single empty hash
-
Uses
DEFAULT
VALUES - single hash
-
Most common format, treats keys as columns and values as values
- single array
-
Treats entries as values, with no columns
- two arrays
-
Treats first array as columns, second array as values
- single
Dataset
-
Treats as an insert based on a selection from the dataset given, with no columns
- array and dataset
-
Treats as an insert based on a selection from the dataset given, with the columns given by the array.
Examples:
DB[:items].insert # INSERT INTO items DEFAULT VALUES DB[:items].insert({}) # INSERT INTO items DEFAULT VALUES DB[:items].insert([1,2,3]) # INSERT INTO items VALUES (1, 2, 3) DB[:items].insert([:a, :b], [1,2]) # INSERT INTO items (a, b) VALUES (1, 2) DB[:items].insert(a: 1, b: 2) # INSERT INTO items (a, b) VALUES (1, 2) DB[:items].insert(DB[:old_items]) # INSERT INTO items SELECT * FROM old_items DB[:items].insert([:a, :b], DB[:old_items]) # INSERT INTO items (a, b) SELECT * FROM old_items
Source
# File lib/sequel/dataset/actions.rb 445 def last(*args, &block) 446 raise(Error, 'No order specified') unless @opts[:order] 447 reverse.first(*args, &block) 448 end
Reverses the order and then runs first
with the given arguments and block. Note that this will not necessarily give you the last record in the dataset, unless you have an unambiguous order. If there is not currently an order for this dataset, raises an Error
.
DB[:table].order(:id).last # SELECT * FROM table ORDER BY id DESC LIMIT 1 # => {:id=>10} DB[:table].order(Sequel.desc(:id)).last(2) # SELECT * FROM table ORDER BY id ASC LIMIT 2 # => [{:id=>1}, {:id=>2}]
Source
# File lib/sequel/dataset/actions.rb 464 def map(column=nil, &block) 465 if column 466 raise(Error, 'Must call Dataset#map with either an argument or a block, not both') if block 467 return naked.map(column) if row_proc 468 if column.is_a?(Array) 469 super(){|r| r.values_at(*column)} 470 else 471 super(){|r| r[column]} 472 end 473 else 474 super(&block) 475 end 476 end
Maps column values for each record in the dataset (if an argument is given) or performs the stock mapping functionality of Enumerable
otherwise. Raises an Error
if both an argument and block are given.
DB[:table].map(:id) # SELECT * FROM table # => [1, 2, 3, ...] DB[:table].map{|r| r[:id] * 2} # SELECT * FROM table # => [2, 4, 6, ...]
You can also provide an array of column names:
DB[:table].map([:id, :name]) # SELECT * FROM table # => [[1, 'A'], [2, 'B'], [3, 'C'], ...]
Source
# File lib/sequel/dataset/actions.rb 485 def max(arg=(no_arg = true), &block) 486 arg = Sequel.virtual_row(&block) if no_arg 487 _aggregate(:max, arg) 488 end
Returns the maximum value for the given column/expression. Uses a virtual row block if no argument is given.
DB[:table].max(:id) # SELECT max(id) FROM table LIMIT 1 # => 10 DB[:table].max{function(column)} # SELECT max(function(column)) FROM table LIMIT 1 # => 7
Source
# File lib/sequel/dataset/actions.rb 535 def merge 536 execute_ddl(merge_sql) 537 end
Execute a MERGE statement, which allows for INSERT, UPDATE, and DELETE behavior in a single query, based on whether rows from a source table match rows in the current table, based on the join conditions.
Unless the dataset uses static SQL
, to use merge
, you must first have called merge_using
to specify the merge source and join conditions. You will then likely to call one or more of the following methods to specify MERGE behavior by adding WHEN [NOT] MATCHED clauses:
The WHEN [NOT] MATCHED clauses are added to the SQL
in the order these methods were called on the dataset. If none of these methods are called, an error is raised.
Example:
DB[:m1] merge_using(:m2, i1: :i2). merge_insert(i1: :i2, a: Sequel[:b]+11). merge_delete{a > 30}. merge_update(i1: Sequel[:i1]+:i2+10, a: Sequel[:a]+:b+20). merge
SQL:
MERGE INTO m1 USING m2 ON (i1 = i2) WHEN NOT MATCHED THEN INSERT (i1, a) VALUES (i2, (b + 11)) WHEN MATCHED AND (a > 30) THEN DELETE WHEN MATCHED THEN UPDATE SET i1 = (i1 + i2 + 10), a = (a + b + 20)
On PostgreSQL, two additional merge methods are supported, for the PostgreSQL-specific DO NOTHING syntax.
-
merge_do_nothing_when_matched
-
merge_do_nothing_when_not_matched
This method is supported on Oracle
, but Oracle’s MERGE support is non-standard, and has the following issues:
-
DELETE clause requires UPDATE clause
-
DELETE clause requires a condition
-
DELETE clause only affects rows updated by UPDATE clause
Source
# File lib/sequel/dataset/actions.rb 546 def min(arg=(no_arg = true), &block) 547 arg = Sequel.virtual_row(&block) if no_arg 548 _aggregate(:min, arg) 549 end
Returns the minimum value for the given column/expression. Uses a virtual row block if no argument is given.
DB[:table].min(:id) # SELECT min(id) FROM table LIMIT 1 # => 1 DB[:table].min{function(column)} # SELECT min(function(column)) FROM table LIMIT 1 # => 0
Source
# File lib/sequel/dataset/actions.rb 563 def multi_insert(hashes, opts=OPTS) 564 return if hashes.empty? 565 columns = hashes.first.keys 566 import(columns, hashes.map{|h| columns.map{|c| h[c]}}, opts) 567 end
This is a front end for import that allows you to submit an array of hashes instead of arrays of columns and values:
DB[:table].multi_insert([{x: 1}, {x: 2}]) # INSERT INTO table (x) VALUES (1) # INSERT INTO table (x) VALUES (2)
Be aware that all hashes should have the same keys if you use this calling method, otherwise some columns could be missed or set to null instead of to default values.
This respects the same options as import
.
Source
# File lib/sequel/dataset/actions.rb 626 def paged_each(opts=OPTS) 627 unless @opts[:order] 628 raise Sequel::Error, "Dataset#paged_each requires the dataset be ordered" 629 end 630 unless defined?(yield) 631 return enum_for(:paged_each, opts) 632 end 633 634 total_limit = @opts[:limit] 635 offset = @opts[:offset] 636 if server = @opts[:server] 637 opts = Hash[opts] 638 opts[:server] = server 639 end 640 641 rows_per_fetch = opts[:rows_per_fetch] || 1000 642 strategy = if offset || total_limit 643 :offset 644 else 645 opts[:strategy] || :offset 646 end 647 648 db.transaction(opts) do 649 case strategy 650 when :filter 651 filter_values = opts[:filter_values] || proc{|row, exprs| exprs.map{|e| row[hash_key_symbol(e)]}} 652 base_ds = ds = limit(rows_per_fetch) 653 while ds 654 last_row = nil 655 ds.each do |row| 656 last_row = row 657 yield row 658 end 659 ds = (base_ds.where(ignore_values_preceding(last_row, &filter_values)) if last_row) 660 end 661 else 662 offset ||= 0 663 num_rows_yielded = rows_per_fetch 664 total_rows = 0 665 666 while num_rows_yielded == rows_per_fetch && (total_limit.nil? || total_rows < total_limit) 667 if total_limit && total_rows + rows_per_fetch > total_limit 668 rows_per_fetch = total_limit - total_rows 669 end 670 671 num_rows_yielded = 0 672 limit(rows_per_fetch, offset).each do |row| 673 num_rows_yielded += 1 674 total_rows += 1 if total_limit 675 yield row 676 end 677 678 offset += rows_per_fetch 679 end 680 end 681 end 682 683 self 684 end
Yields each row in the dataset, but internally uses multiple queries as needed to process the entire result set without keeping all rows in the dataset in memory, even if the underlying driver buffers all query results in memory.
Because this uses multiple queries internally, in order to remain consistent, it also uses a transaction internally. Additionally, to work correctly, the dataset must have unambiguous order. Using an ambiguous order can result in an infinite loop, as well as subtler bugs such as yielding duplicate rows or rows being skipped.
Sequel
checks that the datasets using this method have an order, but it cannot ensure that the order is unambiguous.
Note that this method is not safe to use on many adapters if you are running additional queries inside the provided block. If you are running queries inside the block, use a separate thread or shard inside paged_each
.
Options:
- :rows_per_fetch
-
The number of rows to fetch per query. Defaults to 1000.
- :strategy
-
The strategy to use for paging of results. By default this is :offset, for using an approach with a limit and offset for every page. This can be set to :filter, which uses a limit and a filter that excludes rows from previous pages. In order for this strategy to work, you must be selecting the columns you are ordering by, and none of the columns can contain NULLs. Note that some
Sequel
adapters have optimized implementations that will use cursors or streaming regardless of the :strategy option used. - :filter_values
-
If the strategy: :filter option is used, this option should be a proc that accepts the last retrieved row for the previous page and an array of ORDER BY expressions, and returns an array of values relating to those expressions for the last retrieved row. You will need to use this option if your ORDER BY expressions are not simple columns, if they contain qualified identifiers that would be ambiguous unqualified, if they contain any identifiers that are aliased in SELECT, and potentially other cases.
- :skip_transaction
-
Do not use a transaction. This can be useful if you want to prevent a lock on the database table, at the expense of consistency.
Examples:
DB[:table].order(:id).paged_each{|row| } # SELECT * FROM table ORDER BY id LIMIT 1000 # SELECT * FROM table ORDER BY id LIMIT 1000 OFFSET 1000 # ... DB[:table].order(:id).paged_each(rows_per_fetch: 100){|row| } # SELECT * FROM table ORDER BY id LIMIT 100 # SELECT * FROM table ORDER BY id LIMIT 100 OFFSET 100 # ... DB[:table].order(:id).paged_each(strategy: :filter){|row| } # SELECT * FROM table ORDER BY id LIMIT 1000 # SELECT * FROM table WHERE id > 1001 ORDER BY id LIMIT 1000 # ... DB[:table].order(:id).paged_each(strategy: :filter, filter_values: lambda{|row, exprs| [row[:id]]}){|row| } # SELECT * FROM table ORDER BY id LIMIT 1000 # SELECT * FROM table WHERE id > 1001 ORDER BY id LIMIT 1000 # ...
Source
# File lib/sequel/dataset/actions.rb 704 def select_hash(key_column, value_column, opts = OPTS) 705 _select_hash(:as_hash, key_column, value_column, opts) 706 end
Returns a hash with key_column values as keys and value_column values as values. Similar to as_hash
, but only selects the columns given. Like as_hash
, it accepts an optional :hash parameter, into which entries will be merged.
DB[:table].select_hash(:id, :name) # SELECT id, name FROM table # => {1=>'a', 2=>'b', ...}
You can also provide an array of column names for either the key_column, the value column, or both:
DB[:table].select_hash([:id, :foo], [:name, :bar]) # SELECT id, foo, name, bar FROM table # => {[1, 3]=>['a', 'c'], [2, 4]=>['b', 'd'], ...}
When using this method, you must be sure that each expression has an alias that Sequel
can determine.
Source
# File lib/sequel/dataset/actions.rb 725 def select_hash_groups(key_column, value_column, opts = OPTS) 726 _select_hash(:to_hash_groups, key_column, value_column, opts) 727 end
Returns a hash with key_column values as keys and an array of value_column values. Similar to to_hash_groups
, but only selects the columns given. Like to_hash_groups
, it accepts an optional :hash parameter, into which entries will be merged.
DB[:table].select_hash_groups(:name, :id) # SELECT id, name FROM table # => {'a'=>[1, 4, ...], 'b'=>[2, ...], ...}
You can also provide an array of column names for either the key_column, the value column, or both:
DB[:table].select_hash_groups([:first, :middle], [:last, :id]) # SELECT first, middle, last, id FROM table # => {['a', 'b']=>[['c', 1], ['d', 2], ...], ...}
When using this method, you must be sure that each expression has an alias that Sequel
can determine.
Source
# File lib/sequel/dataset/actions.rb 748 def select_map(column=nil, &block) 749 _select_map(column, false, &block) 750 end
Selects the column given (either as an argument or as a block), and returns an array of all values of that column in the dataset. If you give a block argument that returns an array with multiple entries, the contents of the resulting array are undefined. Raises an Error
if called with both an argument and a block.
DB[:table].select_map(:id) # SELECT id FROM table # => [3, 5, 8, 1, ...] DB[:table].select_map{id * 2} # SELECT (id * 2) FROM table # => [6, 10, 16, 2, ...]
You can also provide an array of column names:
DB[:table].select_map([:id, :name]) # SELECT id, name FROM table # => [[1, 'A'], [2, 'B'], [3, 'C'], ...]
If you provide an array of expressions, you must be sure that each entry in the array has an alias that Sequel
can determine.
Source
# File lib/sequel/dataset/actions.rb 767 def select_order_map(column=nil, &block) 768 _select_map(column, true, &block) 769 end
The same as select_map
, but in addition orders the array by the column.
DB[:table].select_order_map(:id) # SELECT id FROM table ORDER BY id # => [1, 2, 3, 4, ...] DB[:table].select_order_map{id * 2} # SELECT (id * 2) FROM table ORDER BY (id * 2) # => [2, 4, 6, 8, ...]
You can also provide an array of column names:
DB[:table].select_order_map([:id, :name]) # SELECT id, name FROM table ORDER BY id, name # => [[1, 'A'], [2, 'B'], [3, 'C'], ...]
If you provide an array of expressions, you must be sure that each entry in the array has an alias that Sequel
can determine.
Source
# File lib/sequel/dataset/actions.rb 777 def single_record 778 _single_record_ds.single_record! 779 end
Limits the dataset to one record, and returns the first record in the dataset, or nil if the dataset has no records. Users should probably use first
instead of this method. Example:
DB[:test].single_record # SELECT * FROM test LIMIT 1 # => {:column_name=>'value'}
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# File lib/sequel/dataset/actions.rb 789 def single_record! 790 with_sql_first(select_sql) 791 end
Returns the first record in dataset, without limiting the dataset. Returns nil if the dataset has no records. Users should probably use first
instead of this method. This should only be used if you know the dataset is already limited to a single record. This method may be desirable to use for performance reasons, as it does not clone the receiver. Example:
DB[:test].single_record! # SELECT * FROM test # => {:column_name=>'value'}
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# File lib/sequel/dataset/actions.rb 799 def single_value 800 single_value_ds.each do |r| 801 r.each{|_, v| return v} 802 end 803 nil 804 end
Returns the first value of the first record in the dataset. Returns nil if dataset is empty. Users should generally use get
instead of this method. Example:
DB[:test].single_value # SELECT * FROM test LIMIT 1 # => 'value'
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# File lib/sequel/dataset/actions.rb 814 def single_value! 815 with_sql_single_value(select_sql) 816 end
Returns the first value of the first record in the dataset, without limiting the dataset. Returns nil if the dataset is empty. Users should generally use get
instead of this method. Should not be used on graphed datasets or datasets that have row_procs that don’t return hashes. This method may be desirable to use for performance reasons, as it does not clone the receiver.
DB[:test].single_value! # SELECT * FROM test # => 'value'
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# File lib/sequel/dataset/actions.rb 825 def sum(arg=(no_arg = true), &block) 826 arg = Sequel.virtual_row(&block) if no_arg 827 _aggregate(:sum, arg) 828 end
Returns the sum for the given column/expression. Uses a virtual row block if no column is given.
DB[:table].sum(:id) # SELECT sum(id) FROM table LIMIT 1 # => 55 DB[:table].sum{function(column)} # SELECT sum(function(column)) FROM table LIMIT 1 # => 10
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# File lib/sequel/dataset/actions.rb 882 def to_hash(*a) 883 as_hash(*a) 884 end
Alias of as_hash
for backwards compatibility.
Source
# File lib/sequel/dataset/actions.rb 910 def to_hash_groups(key_column, value_column = nil, opts = OPTS) 911 h = opts[:hash] || {} 912 meth = opts[:all] ? :all : :each 913 if value_column 914 return naked.to_hash_groups(key_column, value_column, opts) if row_proc 915 if value_column.is_a?(Array) 916 if key_column.is_a?(Array) 917 public_send(meth){|r| (h[r.values_at(*key_column)] ||= []) << r.values_at(*value_column)} 918 else 919 public_send(meth){|r| (h[r[key_column]] ||= []) << r.values_at(*value_column)} 920 end 921 else 922 if key_column.is_a?(Array) 923 public_send(meth){|r| (h[r.values_at(*key_column)] ||= []) << r[value_column]} 924 else 925 public_send(meth){|r| (h[r[key_column]] ||= []) << r[value_column]} 926 end 927 end 928 elsif key_column.is_a?(Array) 929 public_send(meth){|r| (h[key_column.map{|k| r[k]}] ||= []) << r} 930 else 931 public_send(meth){|r| (h[r[key_column]] ||= []) << r} 932 end 933 h 934 end
Returns a hash with one column used as key and the values being an array of column values. If the value_column is not given or nil, uses the entire hash as the value.
DB[:table].to_hash_groups(:name, :id) # SELECT * FROM table # {'Jim'=>[1, 4, 16, ...], 'Bob'=>[2], ...} DB[:table].to_hash_groups(:name) # SELECT * FROM table # {'Jim'=>[{:id=>1, :name=>'Jim'}, {:id=>4, :name=>'Jim'}, ...], 'Bob'=>[{:id=>2, :name=>'Bob'}], ...}
You can also provide an array of column names for either the key_column, the value column, or both:
DB[:table].to_hash_groups([:first, :middle], [:last, :id]) # SELECT * FROM table # {['Jim', 'Bob']=>[['Smith', 1], ['Jackson', 4], ...], ...} DB[:table].to_hash_groups([:first, :middle]) # SELECT * FROM table # {['Jim', 'Bob']=>[{:id=>1, :first=>'Jim', :middle=>'Bob', :last=>'Smith'}, ...], ...}
Options:
- :all
-
Use all instead of each to retrieve the objects
- :hash
-
The object into which the values will be placed. If this is not given, an empty hash is used. This can be used to use a hash with a default value or default proc.
Source
# File lib/sequel/dataset/actions.rb 940 def truncate 941 execute_ddl(truncate_sql) 942 end
Truncates the dataset. Returns nil.
DB[:table].truncate # TRUNCATE table # => nil
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# File lib/sequel/dataset/actions.rb 966 def update(values=OPTS, &block) 967 sql = update_sql(values) 968 if uses_returning?(:update) 969 returning_fetch_rows(sql, &block) 970 else 971 execute_dui(sql) 972 end 973 end
Updates values for the dataset. The returned value is the number of rows updated. values
should be a hash where the keys are columns to set and values are the values to which to set the columns.
DB[:table].update(x: nil) # UPDATE table SET x = NULL # => 10 DB[:table].update(x: Sequel[:x]+1, y: 0) # UPDATE table SET x = (x + 1), y = 0 # => 10
Some databases support using multiple tables in an UPDATE query. This requires multiple FROM tables (JOINs can also be used). As multiple FROM tables use an implicit CROSS JOIN, you should make sure your WHERE condition uses the appropriate filters for the FROM tables:
DB.from(:a, :b).join(:c, :d=>Sequel[:b][:e]).where{{a[:f]=>b[:g], a[:id]=>10}}. update(:f=>Sequel[:c][:h]) # UPDATE a # SET f = c.h # FROM b # INNER JOIN c ON (c.d = b.e) # WHERE ((a.f = b.g) AND (a.id = 10))
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# File lib/sequel/dataset/actions.rb 981 def where_all(cond, &block) 982 if loader = _where_loader([cond], nil) 983 loader.all(filter_expr(cond), &block) 984 else 985 where(cond).all(&block) 986 end 987 end
Return an array of all rows matching the given filter condition, also yielding each row to the given block. Basically the same as where(cond).all(&block), except it can be optimized to not create an intermediate dataset.
DB[:table].where_all(id: [1,2,3]) # SELECT * FROM table WHERE (id IN (1, 2, 3))
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# File lib/sequel/dataset/actions.rb 995 def where_each(cond, &block) 996 if loader = _where_loader([cond], nil) 997 loader.each(filter_expr(cond), &block) 998 else 999 where(cond).each(&block) 1000 end 1001 end
Iterate over all rows matching the given filter condition, yielding each row to the given block. Basically the same as where(cond).each(&block), except it can be optimized to not create an intermediate dataset.
DB[:table].where_each(id: [1,2,3]){|row| p row} # SELECT * FROM table WHERE (id IN (1, 2, 3))
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# File lib/sequel/dataset/actions.rb 1010 def where_single_value(cond) 1011 if loader = cached_where_placeholder_literalizer([cond], nil, :_where_single_value_loader) do |pl| 1012 single_value_ds.where(pl.arg) 1013 end 1014 1015 loader.get(filter_expr(cond)) 1016 else 1017 where(cond).single_value 1018 end 1019 end
Filter the datasets using the given filter condition, then return a single value. This assumes that the dataset has already been setup to limit the selection to a single column. Basically the same as where(cond).single_value, except it can be optimized to not create an intermediate dataset.
DB[:table].select(:name).where_single_value(id: 1) # SELECT name FROM table WHERE (id = 1) LIMIT 1
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# File lib/sequel/dataset/actions.rb 1023 def with_sql_all(sql, &block) 1024 _all(block){|a| with_sql_each(sql){|r| a << r}} 1025 end
Run the given SQL
and return an array of all rows. If a block is given, each row is yielded to the block after all rows are loaded. See with_sql_each.
Source
# File lib/sequel/dataset/actions.rb 1030 def with_sql_delete(sql) 1031 execute_dui(sql) 1032 end
Execute the given SQL
and return the number of rows deleted. This exists solely as an optimization, replacing with_sql
(sql).delete. It’s significantly faster as it does not require cloning the current dataset.
Source
# File lib/sequel/dataset/actions.rb 1036 def with_sql_each(sql) 1037 if rp = row_proc 1038 _with_sql_dataset.fetch_rows(sql){|r| yield rp.call(r)} 1039 else 1040 _with_sql_dataset.fetch_rows(sql){|r| yield r} 1041 end 1042 self 1043 end
Run the given SQL
and yield each returned row to the block.
Source
# File lib/sequel/dataset/actions.rb 1047 def with_sql_first(sql) 1048 with_sql_each(sql){|r| return r} 1049 nil 1050 end
Run the given SQL
and return the first row, or nil if no rows were returned. See with_sql_each.
Source
# File lib/sequel/dataset/actions.rb 1063 def with_sql_insert(sql) 1064 execute_insert(sql) 1065 end
Execute the given SQL
and (on most databases) return the primary key of the inserted row.
Source
# File lib/sequel/dataset/actions.rb 1055 def with_sql_single_value(sql) 1056 if r = with_sql_first(sql) 1057 r.each{|_, v| return v} 1058 end 1059 end
Run the given SQL
and return the first value in the first row, or nil if no rows were returned. For this to make sense, the SQL
given should select only a single value. See with_sql_each.
Protected Instance Methods
Source
# File lib/sequel/dataset/actions.rb 1073 def _import(columns, values, opts) 1074 trans_opts = Hash[opts] 1075 trans_opts[:server] = @opts[:server] 1076 if opts[:return] == :primary_key 1077 _import_transaction(values, trans_opts){values.map{|v| insert(columns, v)}} 1078 else 1079 stmts = multi_insert_sql(columns, values) 1080 _import_transaction(stmts, trans_opts){stmts.each{|st| execute_dui(st)}} 1081 end 1082 end
Internals of import
. If primary key values are requested, use separate insert commands for each row. Otherwise, call multi_insert_sql
and execute each statement it gives separately. A transaction is only used if there are multiple statements to execute.
Source
# File lib/sequel/dataset/actions.rb 1085 def _select_map_multiple(ret_cols) 1086 map{|r| r.values_at(*ret_cols)} 1087 end
Return an array of arrays of values given by the symbols in ret_cols.
Source
# File lib/sequel/dataset/actions.rb 1090 def _select_map_single 1091 k = nil 1092 map{|r| r[k||=r.keys.first]} 1093 end
Returns an array of the first value in each row.
Source
# File lib/sequel/dataset/actions.rb 1096 def single_value_ds 1097 clone(:limit=>1).ungraphed.naked 1098 end
A dataset for returning single values from the current dataset.
Private Instance Methods
Source
# File lib/sequel/dataset/actions.rb 1112 def _aggregate(function, arg) 1113 if loader = cached_placeholder_literalizer(:"_#{function}_loader") do |pl| 1114 aggregate_dataset.limit(1).select(SQL::Function.new(function, pl.arg).as(function)) 1115 end 1116 loader.get(arg) 1117 else 1118 aggregate_dataset.get(SQL::Function.new(function, arg).as(function)) 1119 end 1120 end
Cached placeholder literalizer for methods that return values using aggregate functions.
Source
# File lib/sequel/dataset/actions.rb 1103 def _all(block) 1104 a = [] 1105 yield a 1106 post_load(a) 1107 a.each(&block) if block 1108 a 1109 end
Internals of all and with_sql_all
Source
# File lib/sequel/dataset/actions.rb 1220 def _hash_key_symbol(s, recursing=false) 1221 case s 1222 when Symbol 1223 _, c, a = split_symbol(s) 1224 (a || c).to_sym 1225 when SQL::Identifier, SQL::Wrapper 1226 _hash_key_symbol(s.value, true) 1227 when SQL::QualifiedIdentifier 1228 _hash_key_symbol(s.column, true) 1229 when SQL::AliasedExpression 1230 _hash_key_symbol(s.alias, true) 1231 when String 1232 s.to_sym if recursing 1233 end 1234 end
Return a plain symbol given a potentially qualified or aliased symbol, specifying the symbol that is likely to be used as the hash key for the column when records are returned. Return nil if no hash key can be determined
Source
# File lib/sequel/dataset/actions.rb 1125 def _import_transaction(values, trans_opts, &block) 1126 # OK to mutate trans_opts as it is generated by _import 1127 trans_opts[:skip_transaction] = true if values.length <= 1 1128 @db.transaction(trans_opts, &block) 1129 end
Use a transaction when yielding to the block if multiple values/statements are provided. When only a single value or statement is provided, then yield without using a transaction.
Source
# File lib/sequel/dataset/actions.rb 1132 def _select_hash(meth, key_column, value_column, opts=OPTS) 1133 select(*(key_column.is_a?(Array) ? key_column : [key_column]) + (value_column.is_a?(Array) ? value_column : [value_column])). 1134 public_send(meth, hash_key_symbols(key_column), hash_key_symbols(value_column), opts) 1135 end
Internals of select_hash
and select_hash_groups
Source
# File lib/sequel/dataset/actions.rb 1138 def _select_map(column, order, &block) 1139 ds = ungraphed.naked 1140 columns = Array(column) 1141 virtual_row_columns(columns, block) 1142 select_cols = order ? columns.map{|c| c.is_a?(SQL::OrderedExpression) ? c.expression : c} : columns 1143 ds = ds.order(*columns.map{|c| unaliased_identifier(c)}) if order 1144 if column.is_a?(Array) || (columns.length > 1) 1145 ds.select(*select_cols)._select_map_multiple(hash_key_symbols(select_cols)) 1146 else 1147 ds.select(auto_alias_expression(select_cols.first))._select_map_single 1148 end 1149 end
Internals of select_map
and select_order_map
Source
# File lib/sequel/dataset/actions.rb 1152 def _single_record_ds 1153 cached_dataset(:_single_record_ds){clone(:limit=>1)} 1154 end
A cached dataset for a single record for this dataset.
Source
# File lib/sequel/dataset/actions.rb 1157 def _where_loader(where_args, where_block) 1158 cached_where_placeholder_literalizer(where_args, where_block, :_where_loader) do |pl| 1159 where(pl.arg) 1160 end 1161 end
Loader used for where_all
and where_each.
Source
# File lib/sequel/dataset/actions.rb 1338 def _with_sql_dataset 1339 if @opts[:_with_sql_ds] 1340 self 1341 else 1342 cached_dataset(:_with_sql_ds) do 1343 clone(:_with_sql_ds=>true) 1344 end 1345 end 1346 end
Cached dataset to use for with_sql_#{all,each,first,single_value}. This is used so that the columns returned by the given SQL
do not affect the receiver of the with_sql_* method.
Source
# File lib/sequel/dataset/actions.rb 1164 def auto_alias_expression(v) 1165 case v 1166 when LiteralString, Symbol, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression 1167 v 1168 else 1169 SQL::AliasedExpression.new(v, :v) 1170 end 1171 end
Automatically alias the given expression if it does not have an identifiable alias.
Source
# File lib/sequel/dataset/actions.rb 1175 def default_import_slice 1176 nil 1177 end
The default number of rows that can be inserted in a single INSERT statement via import. The default is for no limit.
Source
# File lib/sequel/dataset/actions.rb 1180 def default_server_opts(opts) 1181 if @db.sharded? && !opts.has_key?(:server) 1182 opts = Hash[opts] 1183 opts[:server] = @opts[:server] || :default 1184 end 1185 opts 1186 end
Set the server to use to :default unless it is already set in the passed opts
Source
# File lib/sequel/dataset/actions.rb 1190 def execute(sql, opts=OPTS, &block) 1191 db = @db 1192 if db.sharded? && !opts.has_key?(:server) 1193 opts = Hash[opts] 1194 opts[:server] = @opts[:server] || (@opts[:lock] ? :default : :read_only) 1195 opts 1196 end 1197 db.execute(sql, opts, &block) 1198 end
Execute the given select SQL
on the database using execute. Use the :read_only server unless a specific server is set.
Source
# File lib/sequel/dataset/actions.rb 1201 def execute_ddl(sql, opts=OPTS, &block) 1202 @db.execute_ddl(sql, default_server_opts(opts), &block) 1203 nil 1204 end
Execute the given SQL
on the database using execute_ddl.
Source
# File lib/sequel/dataset/actions.rb 1207 def execute_dui(sql, opts=OPTS, &block) 1208 @db.execute_dui(sql, default_server_opts(opts), &block) 1209 end
Execute the given SQL
on the database using execute_dui.
Source
# File lib/sequel/dataset/actions.rb 1212 def execute_insert(sql, opts=OPTS, &block) 1213 @db.execute_insert(sql, default_server_opts(opts), &block) 1214 end
Execute the given SQL
on the database using execute_insert.
Source
# File lib/sequel/dataset/actions.rb 1240 def hash_key_symbol(s) 1241 if v = _hash_key_symbol(s) 1242 v 1243 else 1244 raise(Error, "#{s.inspect} is not supported, should be a Symbol, SQL::Identifier, SQL::QualifiedIdentifier, or SQL::AliasedExpression") 1245 end 1246 end
Return a plain symbol given a potentially qualified or aliased symbol, specifying the symbol that is likely to be used as the hash key for the column when records are returned. Raise Error
if the hash key symbol cannot be returned.
Source
# File lib/sequel/dataset/actions.rb 1251 def hash_key_symbols(s) 1252 s.is_a?(Array) ? s.map{|c| hash_key_symbol(c)} : hash_key_symbol(s) 1253 end
If s is an array, return an array with the given hash key symbols. Otherwise, return a hash key symbol for the given expression If a hash key symbol cannot be determined, raise an error.
Source
# File lib/sequel/dataset/actions.rb 1258 def ignore_values_preceding(row) 1259 @opts[:order].map{|v| v.is_a?(SQL::OrderedExpression) ? v.expression : v} 1260 1261 order_exprs = @opts[:order].map do |v| 1262 if v.is_a?(SQL::OrderedExpression) 1263 descending = v.descending 1264 v = v.expression 1265 else 1266 descending = false 1267 end 1268 [v, descending] 1269 end 1270 1271 row_values = yield(row, order_exprs.map(&:first)) 1272 1273 last_expr = [] 1274 cond = order_exprs.zip(row_values).map do |(v, descending), value| 1275 expr = last_expr + [SQL::BooleanExpression.new(descending ? :< : :>, v, value)] 1276 last_expr += [SQL::BooleanExpression.new(:'=', v, value)] 1277 Sequel.&(*expr) 1278 end 1279 Sequel.|(*cond) 1280 end
Returns an expression that will ignore values preceding the given row, using the receiver’s current order. This yields the row and the array of order expressions to the block, which should return an array of values to use.
Source
# File lib/sequel/dataset/actions.rb 1283 def output_identifier(v) 1284 v = 'untitled' if v == '' 1285 v.to_s.downcase.to_sym 1286 end
Downcase identifiers by default when outputing them from the database.
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# File lib/sequel/dataset/actions.rb 1292 def post_load(all_records) 1293 end
This is run inside .all, after all of the records have been loaded via .each, but before any block passed to all is called. It is called with a single argument, an array of all returned records. Does nothing by default, added to make the model eager loading code simpler.
Source
# File lib/sequel/dataset/actions.rb 1298 def returning_fetch_rows(sql, &block) 1299 if block 1300 default_server.fetch_rows(sql, &block) 1301 nil 1302 else 1303 rows = [] 1304 default_server.fetch_rows(sql){|r| rows << r} 1305 rows 1306 end 1307 end
Called by insert/update/delete when returning is used. Yields each row as a plain hash to the block if one is given, or returns an array of plain hashes for all rows if a block is not given
Source
# File lib/sequel/dataset/actions.rb 1312 def unaliased_identifier(c) 1313 case c 1314 when Symbol 1315 table, column, aliaz = split_symbol(c) 1316 if aliaz 1317 table ? SQL::QualifiedIdentifier.new(table, column) : Sequel.identifier(column) 1318 else 1319 c 1320 end 1321 when SQL::AliasedExpression 1322 c.expression 1323 when SQL::OrderedExpression 1324 case expr = c.expression 1325 when Symbol, SQL::AliasedExpression 1326 SQL::OrderedExpression.new(unaliased_identifier(expr), c.descending, :nulls=>c.nulls) 1327 else 1328 c 1329 end 1330 else 1331 c 1332 end 1333 end
Return the unaliased part of the identifier. Handles both implicit aliases in symbols, as well as SQL::AliasedExpression
objects. Other objects are returned as is.
3 - User Methods relating to SQL Creation
↑ topPublic Instance Methods
Source
# File lib/sequel/dataset/sql.rb 14 def exists 15 SQL::PlaceholderLiteralString.new(EXISTS, [self], true) 16 end
Returns an EXISTS
clause for the dataset as an SQL::PlaceholderLiteralString
.
DB.select(1).where(DB[:items].exists) # SELECT 1 WHERE (EXISTS (SELECT * FROM items))
Source
# File lib/sequel/dataset/sql.rb 22 def insert_sql(*values) 23 return static_sql(@opts[:sql]) if @opts[:sql] 24 25 check_insert_allowed! 26 27 columns, values = _parse_insert_sql_args(values) 28 if values.is_a?(Array) && values.empty? && !insert_supports_empty_values? 29 columns, values = insert_empty_columns_values 30 elsif values.is_a?(Dataset) && hoist_cte?(values) && supports_cte?(:insert) 31 ds, values = hoist_cte(values) 32 return ds.clone(:columns=>columns, :values=>values).send(:_insert_sql) 33 end 34 clone(:columns=>columns, :values=>values).send(:_insert_sql) 35 end
Returns an INSERT SQL
query string. See insert
.
DB[:items].insert_sql(a: 1) # => "INSERT INTO items (a) VALUES (1)"
Source
# File lib/sequel/dataset/sql.rb 40 def literal_append(sql, v) 41 case v 42 when Symbol 43 if skip_symbol_cache? 44 literal_symbol_append(sql, v) 45 else 46 unless l = db.literal_symbol(v) 47 l = String.new 48 literal_symbol_append(l, v) 49 db.literal_symbol_set(v, l) 50 end 51 sql << l 52 end 53 when String 54 case v 55 when LiteralString 56 sql << v 57 when SQL::Blob 58 literal_blob_append(sql, v) 59 else 60 literal_string_append(sql, v) 61 end 62 when Integer 63 sql << literal_integer(v) 64 when Hash 65 literal_hash_append(sql, v) 66 when SQL::Expression 67 literal_expression_append(sql, v) 68 when Float 69 sql << literal_float(v) 70 when BigDecimal 71 sql << literal_big_decimal(v) 72 when NilClass 73 sql << literal_nil 74 when TrueClass 75 sql << literal_true 76 when FalseClass 77 sql << literal_false 78 when Array 79 literal_array_append(sql, v) 80 when Time 81 v.is_a?(SQLTime) ? literal_sqltime_append(sql, v) : literal_time_append(sql, v) 82 when DateTime 83 literal_datetime_append(sql, v) 84 when Date 85 literal_date_append(sql, v) 86 when Dataset 87 literal_dataset_append(sql, v) 88 else 89 literal_other_append(sql, v) 90 end 91 end
Append a literal representation of a value to the given SQL
string.
If an unsupported object is given, an Error
is raised.
Source
# File lib/sequel/dataset/sql.rb 123 def literal_date_or_time(dt, raw=false) 124 value = case dt 125 when SQLTime 126 literal_sqltime(dt) 127 when Time 128 literal_time(dt) 129 when DateTime 130 literal_datetime(dt) 131 when Date 132 literal_date(dt) 133 else 134 raise TypeError, "unsupported type: #{dt.inspect}" 135 end 136 137 if raw 138 value.sub!(/\A'/, '') 139 value.sub!(/'\z/, '') 140 end 141 142 value 143 end
Literalize a date or time value, as a SQL
string value with no typecasting. If raw
is true, remove the surrounding single quotes. This is designed for usage by bound argument code that can work even if the auto_cast_date_and_time extension is used (either manually or implicitly in the related adapter).
Source
# File lib/sequel/dataset/sql.rb 94 def merge_sql 95 raise Error, "This database doesn't support MERGE" unless supports_merge? 96 if sql = opts[:sql] 97 return static_sql(sql) 98 end 99 if sql = cache_get(:_merge_sql) 100 return sql 101 end 102 source, join_condition = @opts[:merge_using] 103 raise Error, "No USING clause for MERGE" unless source 104 sql = @opts[:append_sql] || sql_string_origin 105 106 select_with_sql(sql) 107 sql << "MERGE INTO " 108 source_list_append(sql, @opts[:from]) 109 sql << " USING " 110 identifier_append(sql, source) 111 sql << " ON " 112 literal_append(sql, join_condition) 113 _merge_when_sql(sql) 114 cache_set(:_merge_sql, sql) if cache_sql? 115 sql 116 end
The SQL
to use for the MERGE statement.
Source
# File lib/sequel/dataset/sql.rb 148 def multi_insert_sql(columns, values) 149 case multi_insert_sql_strategy 150 when :values 151 sql = LiteralString.new('VALUES ') 152 expression_list_append(sql, values.map{|r| Array(r)}) 153 [insert_sql(columns, sql)] 154 when :union 155 c = false 156 sql = LiteralString.new 157 u = ' UNION ALL SELECT ' 158 f = empty_from_sql 159 values.each do |v| 160 if c 161 sql << u 162 else 163 sql << 'SELECT ' 164 c = true 165 end 166 expression_list_append(sql, v) 167 sql << f if f 168 end 169 [insert_sql(columns, sql)] 170 else 171 values.map{|r| insert_sql(columns, r)} 172 end 173 end
Returns an array of insert statements for inserting multiple records. This method is used by multi_insert
to format insert statements and expects a keys array and and an array of value arrays.
Source
# File lib/sequel/dataset/sql.rb 176 def sql 177 select_sql 178 end
Same as select_sql
, not aliased directly to make subclassing simpler.
Source
# File lib/sequel/dataset/sql.rb 183 def truncate_sql 184 if opts[:sql] 185 static_sql(opts[:sql]) 186 else 187 check_truncation_allowed! 188 check_not_limited!(:truncate) 189 raise(InvalidOperation, "Can't truncate filtered datasets") if opts[:where] || opts[:having] 190 t = String.new 191 source_list_append(t, opts[:from]) 192 _truncate_sql(t) 193 end 194 end
Returns a TRUNCATE SQL
query string. See truncate
DB[:items].truncate_sql # => 'TRUNCATE items'
Source
# File lib/sequel/dataset/sql.rb 203 def update_sql(values = OPTS) 204 return static_sql(opts[:sql]) if opts[:sql] 205 check_update_allowed! 206 check_not_limited!(:update) 207 208 case values 209 when LiteralString 210 # nothing 211 when String 212 raise Error, "plain string passed to Dataset#update is not supported, use Sequel.lit to use a literal string" 213 end 214 215 clone(:values=>values).send(:_update_sql) 216 end
Formats an UPDATE statement using the given values. See update
.
DB[:items].update_sql(price: 100, category: 'software') # => "UPDATE items SET price = 100, category = 'software'
Raises an Error
if the dataset is grouped or includes more than one table.
4 - Methods that describe what the dataset supports
↑ topPublic Instance Methods
Source
# File lib/sequel/dataset/features.rb 19 def provides_accurate_rows_matched? 20 true 21 end
Whether this dataset will provide accurate number of rows matched for delete and update statements, true by default. Accurate in this case is the number of rows matched by the dataset’s filter.
Source
# File lib/sequel/dataset/features.rb 12 def quote_identifiers? 13 @opts.fetch(:quote_identifiers, true) 14 end
Whether this dataset quotes identifiers.
Source
# File lib/sequel/dataset/features.rb 24 def recursive_cte_requires_column_aliases? 25 false 26 end
Whether you must use a column alias list for recursive CTEs, false by default.
Source
# File lib/sequel/dataset/features.rb 41 def requires_placeholder_type_specifiers? 42 false 43 end
Whether type specifiers are required for prepared statement/bound variable argument placeholders (i.e. :bv__integer), false by default.
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# File lib/sequel/dataset/features.rb 33 def requires_sql_standard_datetimes? 34 # SEQUEL6: Remove 35 false 36 end
Whether the dataset requires SQL
standard datetimes. False by default, as most allow strings with ISO 8601 format. Only for backwards compatibility, no longer used internally, do not use in new code.
Source
# File lib/sequel/dataset/features.rb 48 def supports_cte?(type=:select) 49 false 50 end
Whether the dataset supports common table expressions, false by default. If given, type
can be :select, :insert, :update, or :delete, in which case it determines whether WITH is supported for the respective statement type.
Source
# File lib/sequel/dataset/features.rb 55 def supports_cte_in_subqueries? 56 false 57 end
Whether the dataset supports common table expressions in subqueries, false by default. If false, applies the WITH clause to the main query, which can cause issues if multiple WITH clauses use the same name.
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# File lib/sequel/dataset/features.rb 60 def supports_deleting_joins? 61 supports_modifying_joins? 62 end
Whether deleting from joined datasets is supported, false by default.
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# File lib/sequel/dataset/features.rb 67 def supports_derived_column_lists? 68 true 69 end
Whether the database supports derived column lists (e.g. “table_expr AS table_alias(column_alias1, column_alias2, …)”), true by default.
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# File lib/sequel/dataset/features.rb 72 def supports_distinct_on? 73 false 74 end
Whether the dataset supports or can emulate the DISTINCT ON clause, false by default.
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# File lib/sequel/dataset/features.rb 77 def supports_group_cube? 78 false 79 end
Whether the dataset supports CUBE with GROUP BY, false by default.
Source
# File lib/sequel/dataset/features.rb 82 def supports_group_rollup? 83 false 84 end
Whether the dataset supports ROLLUP with GROUP BY, false by default.
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# File lib/sequel/dataset/features.rb 87 def supports_grouping_sets? 88 false 89 end
Whether the dataset supports GROUPING SETS with GROUP BY, false by default.
Source
# File lib/sequel/dataset/features.rb 93 def supports_insert_select? 94 supports_returning?(:insert) 95 end
Whether this dataset supports the insert_select
method for returning all columns values directly from an insert query, false by default.
Source
# File lib/sequel/dataset/features.rb 98 def supports_intersect_except? 99 true 100 end
Whether the dataset supports the INTERSECT and EXCEPT compound operations, true by default.
Source
# File lib/sequel/dataset/features.rb 103 def supports_intersect_except_all? 104 true 105 end
Whether the dataset supports the INTERSECT ALL and EXCEPT ALL compound operations, true by default.
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# File lib/sequel/dataset/features.rb 108 def supports_is_true? 109 true 110 end
Whether the dataset supports the IS TRUE syntax, true by default.
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# File lib/sequel/dataset/features.rb 114 def supports_join_using? 115 true 116 end
Whether the dataset supports the JOIN table USING (column1, …) syntax, true by default. If false, support is emulated using JOIN table ON (table.column1 = other_table.column1).
Source
# File lib/sequel/dataset/features.rb 119 def supports_lateral_subqueries? 120 false 121 end
Whether the dataset supports LATERAL for subqueries in the FROM or JOIN clauses, false by default.
Source
# File lib/sequel/dataset/features.rb 134 def supports_merge? 135 false 136 end
Whether the MERGE statement is supported, false by default.
Source
# File lib/sequel/dataset/features.rb 139 def supports_modifying_joins? 140 false 141 end
Whether modifying joined datasets is supported, false by default.
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# File lib/sequel/dataset/features.rb 145 def supports_multiple_column_in? 146 true 147 end
Whether the IN/NOT IN operators support multiple columns when an array of values is given, true by default.
Source
# File lib/sequel/dataset/features.rb 129 def supports_nowait? 130 false 131 end
Whether the dataset supports skipping raising an error instead of waiting for locked rows when returning data, false by default.
Source
# File lib/sequel/dataset/features.rb 156 def supports_ordered_distinct_on? 157 supports_distinct_on? 158 end
Whether the dataset supports or can fully emulate the DISTINCT ON clause, including respecting the ORDER BY clause, false by default.
Source
# File lib/sequel/dataset/features.rb 161 def supports_placeholder_literalizer? 162 true 163 end
Whether placeholder literalizers are supported, true by default.
Source
# File lib/sequel/dataset/features.rb 166 def supports_regexp? 167 false 168 end
Whether the dataset supports pattern matching by regular expressions, false by default.
Source
# File lib/sequel/dataset/features.rb 171 def supports_replace? 172 false 173 end
Whether the dataset supports REPLACE syntax, false by default.
Source
# File lib/sequel/dataset/features.rb 177 def supports_returning?(type) 178 false 179 end
Whether the RETURNING clause is supported for the given type of query, false by default. type
can be :insert, :update, or :delete.
Source
# File lib/sequel/dataset/features.rb 187 def supports_select_all_and_column? 188 true 189 end
Whether the database supports SELECT *, column FROM table
, true by default.
Source
# File lib/sequel/dataset/features.rb 182 def supports_skip_locked? 183 false 184 end
Whether the dataset supports skipping locked rows when returning data, false by default.
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# File lib/sequel/dataset/features.rb 194 def supports_timestamp_timezones? 195 # SEQUEL6: Remove 196 false 197 end
Whether the dataset supports timezones in literal timestamps, false by default.
Source
# File lib/sequel/dataset/features.rb 201 def supports_timestamp_usecs? 202 true 203 end
Whether the dataset supports fractional seconds in literal timestamps, true by default.
Source
# File lib/sequel/dataset/features.rb 206 def supports_updating_joins? 207 supports_modifying_joins? 208 end
Whether updating joined datasets is supported, false by default.
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# File lib/sequel/dataset/features.rb 235 def supports_where_true? 236 true 237 end
Whether the dataset supports WHERE TRUE (or WHERE 1 for databases that that use 1 for true), true by default.
Source
# File lib/sequel/dataset/features.rb 212 def supports_window_clause? 213 false 214 end
Whether the dataset supports the WINDOW clause to define windows used by multiple window functions, false by default.
Source
# File lib/sequel/dataset/features.rb 224 def supports_window_function_frame_option?(option) 225 case option 226 when :rows, :range, :offset 227 true 228 else 229 false 230 end 231 end
Whether the dataset supports the given window function option. True by default. This should only be called if supports_window_functions? is true. Possible options are :rows, :range, :groups, :offset, :exclude.
Source
# File lib/sequel/dataset/features.rb 217 def supports_window_functions? 218 false 219 end
Whether the dataset supports window functions, false by default.
Private Instance Methods
Source
# File lib/sequel/dataset/features.rb 243 def insert_supports_empty_values? 244 true 245 end
Whether insert(nil) or insert({}) must be emulated by using at least one value.
Source
# File lib/sequel/dataset/features.rb 253 def requires_emulating_nulls_first? 254 false 255 end
Whether ORDER BY col NULLS FIRST/LAST must be emulated.
Source
# File lib/sequel/dataset/features.rb 248 def requires_like_escape? 249 true 250 end
Whether the dataset needs ESCAPE for LIKE for correct behavior.
Source
# File lib/sequel/dataset/features.rb 258 def supports_cte_in_compounds? 259 supports_cte_in_subqueries? 260 end
Whether common table expressions are supported in UNION/INTERSECT/EXCEPT clauses.
Source
# File lib/sequel/dataset/features.rb 264 def supports_filtered_aggregates? 265 false 266 end
Whether the dataset supports the FILTER clause for aggregate functions. If not, support is emulated using CASE.
Source
# File lib/sequel/dataset/features.rb 269 def supports_quoted_function_names? 270 false 271 end
Whether the database supports quoting function names.
Source
# File lib/sequel/dataset/features.rb 275 def uses_returning?(type) 276 opts[:returning] && !@opts[:sql] && supports_returning?(type) 277 end
Whether the RETURNING clause is used for the given dataset. type
can be :insert, :update, or :delete.
Source
# File lib/sequel/dataset/features.rb 280 def uses_with_rollup? 281 false 282 end
Whether the dataset uses WITH ROLLUP/CUBE instead of ROLLUP()/CUBE().
6 - Miscellaneous methods
↑ topAttributes
The database related to this dataset. This is the Database
instance that will execute all of this dataset’s queries.
The hash of options for this dataset, keys are symbols.
Public Class Methods
Source
# File lib/sequel/dataset/misc.rb 25 def initialize(db) 26 @db = db 27 @opts = OPTS 28 @cache = {} 29 freeze 30 end
Constructs a new Dataset
instance with an associated database and options. Datasets are usually constructed by invoking the Database#[]
method:
DB[:posts]
Sequel::Dataset
is an abstract class that is not useful by itself. Each database adapter provides a subclass of Sequel::Dataset
, and has the Database#dataset
method return an instance of that subclass.
Public Instance Methods
Source
# File lib/sequel/dataset/misc.rb 34 def ==(o) 35 o.is_a?(self.class) && db == o.db && opts == o.opts 36 end
Define a hash value such that datasets with the same class, DB, and opts will be considered equal.
Source
# File lib/sequel/dataset/misc.rb 40 def current_datetime 41 Sequel.datetime_class.now 42 end
An object representing the current date or time, should be an instance of Sequel.datetime_class.
Source
# File lib/sequel/dataset/misc.rb 50 def dup 51 self 52 end
Return self, as datasets are always frozen.
Source
# File lib/sequel/dataset/misc.rb 59 def each_server 60 db.servers.each{|s| yield server(s)} 61 end
Yield a dataset for each server in the connection pool that is tied to that server. Intended for use in sharded environments where all servers need to be modified with the same data:
DB[:configs].where(key: 'setting').each_server{|ds| ds.update(value: 'new_value')}
Source
# File lib/sequel/dataset/misc.rb 68 def escape_like(string) 69 string.gsub(/[\\%_]/){|m| "\\#{m}"} 70 end
Returns the string with the LIKE metacharacters (% and _) escaped. Useful for when the LIKE term is a user-provided string where metacharacters should not be recognized. Example:
ds.escape_like("foo\\%_") # 'foo\\\%\_'
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# File lib/sequel/dataset/misc.rb 91 def first_source 92 first_source_alias 93 end
Alias of first_source_alias
Source
# File lib/sequel/dataset/misc.rb 103 def first_source_alias 104 source = @opts[:from] 105 if source.nil? || source.empty? 106 raise Error, 'No source specified for query' 107 end 108 case s = source.first 109 when SQL::AliasedExpression 110 s.alias 111 when Symbol 112 _, _, aliaz = split_symbol(s) 113 aliaz ? aliaz.to_sym : s 114 else 115 s 116 end 117 end
The first source (primary table) for this dataset. If the dataset doesn’t have a table, raises an Error
. If the table is aliased, returns the aliased name.
DB[:table].first_source_alias # => :table DB[Sequel[:table].as(:t)].first_source_alias # => :t
Source
# File lib/sequel/dataset/misc.rb 128 def first_source_table 129 source = @opts[:from] 130 if source.nil? || source.empty? 131 raise Error, 'No source specified for query' 132 end 133 case s = source.first 134 when SQL::AliasedExpression 135 s.expression 136 when Symbol 137 sch, table, aliaz = split_symbol(s) 138 aliaz ? (sch ? SQL::QualifiedIdentifier.new(sch, table) : table.to_sym) : s 139 else 140 s 141 end 142 end
The first source (primary table) for this dataset. If the dataset doesn’t have a table, raises an error. If the table is aliased, returns the original table, not the alias
DB[:table].first_source_table # => :table DB[Sequel[:table].as(:t)].first_source_table # => :table
Source
# File lib/sequel/dataset/misc.rb 74 def freeze 75 @opts.freeze 76 super 77 end
Freeze the opts when freezing the dataset.
Source
# File lib/sequel/dataset/misc.rb 146 def hash 147 [self.class, db, opts].hash 148 end
Define a hash value such that datasets with the same class, DB, and opts, will have the same hash value.
Source
# File lib/sequel/dataset/misc.rb 152 def inspect 153 "#<#{visible_class_name}: #{sql.inspect}>" 154 end
Returns a string representation of the dataset including the class name and the corresponding SQL
select statement.
Source
# File lib/sequel/dataset/misc.rb 157 def joined_dataset? 158 !!((opts[:from].is_a?(Array) && opts[:from].size > 1) || opts[:join]) 159 end
Whether this dataset is a joined dataset (multiple FROM tables or any JOINs).
Source
# File lib/sequel/dataset/misc.rb 162 def placeholder_literalizer_class 163 ::Sequel::Dataset::PlaceholderLiteralizer 164 end
The class to use for placeholder literalizers for the current dataset.
Source
# File lib/sequel/dataset/misc.rb 167 def placeholder_literalizer_loader(&block) 168 placeholder_literalizer_class.loader(self, &block) 169 end
A placeholder literalizer loader for the current dataset.
Source
# File lib/sequel/dataset/misc.rb 173 def row_number_column 174 :x_sequel_row_number_x 175 end
The alias to use for the row_number column, used when emulating OFFSET support and for eager limit strategies
Source
Source
# File lib/sequel/dataset/misc.rb 186 def split_alias(c) 187 case c 188 when Symbol 189 c_table, column, aliaz = split_symbol(c) 190 [c_table ? SQL::QualifiedIdentifier.new(c_table, column.to_sym) : column.to_sym, aliaz] 191 when SQL::AliasedExpression 192 [c.expression, c.alias] 193 when SQL::JoinClause 194 [c.table, c.table_alias] 195 else 196 [c, nil] 197 end 198 end
Splits a possible implicit alias in c
, handling both SQL::AliasedExpressions and Symbols. Returns an array of two elements, with the first being the main expression, and the second being the alias.
Source
# File lib/sequel/dataset/misc.rb 205 def unqualified_column_for(v) 206 unless v.is_a?(String) 207 _unqualified_column_for(v) 208 end 209 end
This returns an SQL::Identifier
or SQL::AliasedExpression
containing an SQL
identifier that represents the unqualified column for the given value. The given value should be a Symbol
, SQL::Identifier
, SQL::QualifiedIdentifier
, or SQL::AliasedExpression
containing one of those. In other cases, this returns nil.
Source
# File lib/sequel/dataset/misc.rb 233 def unused_table_alias(table_alias, used_aliases = []) 234 table_alias = alias_symbol(table_alias) 235 used_aliases += opts[:from].map{|t| alias_symbol(t)} if opts[:from] 236 used_aliases += opts[:join].map{|j| j.table_alias ? alias_alias_symbol(j.table_alias) : alias_symbol(j.table)} if opts[:join] 237 if used_aliases.include?(table_alias) 238 i = 0 239 while true 240 ta = :"#{table_alias}_#{i}" 241 return ta unless used_aliases.include?(ta) 242 i += 1 243 end 244 else 245 table_alias 246 end 247 end
Creates a unique table alias that hasn’t already been used in the dataset. table_alias can be any type of object accepted by alias_symbol. The symbol returned will be the implicit alias in the argument, possibly appended with “_N” if the implicit alias has already been used, where N is an integer starting at 0 and increasing until an unused one is found.
You can provide a second addition array argument containing symbols that should not be considered valid table aliases. The current aliases for the FROM and JOIN tables are automatically included in this array.
DB[:table].unused_table_alias(:t) # => :t DB[:table].unused_table_alias(:table) # => :table_0 DB[:table, :table_0].unused_table_alias(:table) # => :table_1 DB[:table, :table_0].unused_table_alias(:table, [:table_1, :table_2]) # => :table_3
Source
# File lib/sequel/dataset/misc.rb 250 def with_quote_identifiers(v) 251 clone(:quote_identifiers=>v, :skip_symbol_cache=>true) 252 end
Return a modified dataset with quote_identifiers set.
Protected Instance Methods
Source
# File lib/sequel/dataset/misc.rb 281 def _columns 282 cache_get(:_columns) 283 end
The cached columns for the current dataset.
Source
# File lib/sequel/dataset/misc.rb 263 def cache_get(k) 264 Sequel.synchronize{@cache[k]} 265 end
Retreive a value from the dataset’s cache in a thread safe manner.
Source
# File lib/sequel/dataset/misc.rb 268 def cache_set(k, v) 269 Sequel.synchronize{@cache[k] = v} 270 end
Set a value in the dataset’s cache in a thread safe manner.
Source
# File lib/sequel/dataset/misc.rb 276 def clear_columns_cache 277 @cache.delete(:_columns) 278 end
Clear the columns hash for the current dataset. This is not a thread safe operation, so it should only be used if the dataset could not be used by another thread (such as one that was just created via clone).
Private Instance Methods
Source
# File lib/sequel/dataset/misc.rb 355 def _unqualified_column_for(v) 356 case v 357 when Symbol 358 _, c, a = Sequel.split_symbol(v) 359 c = Sequel.identifier(c) 360 a ? c.as(a) : c 361 when String 362 Sequel.identifier(v) 363 when SQL::Identifier 364 v 365 when SQL::QualifiedIdentifier 366 _unqualified_column_for(v.column) 367 when SQL::AliasedExpression 368 if expr = unqualified_column_for(v.expression) 369 SQL::AliasedExpression.new(expr, v.alias) 370 end 371 end 372 end
Internal recursive version of unqualified_column_for
, handling Strings inside of other objects.
Source
# File lib/sequel/dataset/misc.rb 289 def cached_dataset(key) 290 unless ds = cache_get(key) 291 ds = yield 292 cache_set(key, ds) 293 end 294 295 ds 296 end
Check the cache for the given key, returning the value. Otherwise, yield to get the dataset and cache the dataset under the given key.
Source
# File lib/sequel/dataset/misc.rb 303 def cached_placeholder_literalizer(key) 304 if loader = cache_get(key) 305 return loader unless loader.is_a?(Integer) 306 loader += 1 307 308 if loader >= 3 309 loader = placeholder_literalizer_loader{|pl, _| yield pl} 310 cache_set(key, loader) 311 else 312 cache_set(key, loader + 1) 313 loader = nil 314 end 315 elsif cache_sql? && supports_placeholder_literalizer? 316 cache_set(key, 1) 317 end 318 319 loader 320 end
Return a cached placeholder literalizer for the given key if there is one for this dataset. If there isn’t one, increment the counter for the number of calls for the key, and if the counter is at least three, then create a placeholder literalizer by yielding to the block, and cache it.
Source
# File lib/sequel/dataset/misc.rb 327 def cached_where_placeholder_literalizer(where_args, where_block, key, &block) 328 where_args = where_args[0] if where_args.length == 1 329 unless where_block 330 return if where_args == OPTS || where_args == EMPTY_ARRAY 331 end 332 333 cached_placeholder_literalizer(key, &block) 334 end
Return a cached placeholder literalizer for the key, unless where_block is nil and where_args is an empty array or hash. This is designed to guard against placeholder literalizer use when passing arguments to where in the uncached case and filter_expr
if a cached placeholder literalizer is used.
Source
# File lib/sequel/dataset/misc.rb 337 def columns=(v) 338 cache_set(:_columns, v) 339 end
Set the columns for the current dataset.
Source
# File lib/sequel/dataset/misc.rb 342 def initialize_clone(c, _=nil) 343 @db = c.db 344 @opts = Hash[c.opts] 345 if cols = c.cache_get(:_columns) 346 @cache = {:_columns=>cols} 347 else 348 @cache = {} 349 end 350 end
Set the db, opts, and cache for the copy of the dataset.
Source
# File lib/sequel/dataset/misc.rb 375 def visible_class_name 376 c = self.class 377 c = c.superclass while c.name.nil? || c.name == '' 378 c.name 379 end
Return the class name for this dataset, but skip anonymous classes
9 - Internal Methods relating to SQL Creation
↑ topConstants
- BITWISE_METHOD_MAP
- COUNT_FROM_SELF_OPTS
- COUNT_OF_ALL_AS_COUNT
- DEFAULT
- EXISTS
- IS_LITERALS
- IS_OPERATORS
- LIKE_OPERATORS
- MERGE_NORMALIZE_TYPE_MAP
- MERGE_TYPE_SQL
-
Mapping of merge types to related
SQL
- N_ARITY_OPERATORS
- QUALIFY_KEYS
- REGEXP_OPERATORS
- TWO_ARITY_OPERATORS
- WILDCARD
Public Class Methods
Source
# File lib/sequel/dataset/sql.rb 225 def self.clause_methods(type, clauses) 226 clauses.map{|clause| :"#{type}_#{clause}_sql"}.freeze 227 end
Given a type (e.g. select) and an array of clauses, return an array of methods to call to build the SQL
string.
Source
# File lib/sequel/dataset/sql.rb 239 def self.def_sql_method(mod, type, clauses) 240 priv = type == :update || type == :insert 241 cacheable = type == :select || type == :delete 242 243 lines = [] 244 lines << 'private' if priv 245 lines << "def #{'_' if priv}#{type}_sql" 246 lines << 'if sql = opts[:sql]; return static_sql(sql) end' unless priv 247 lines << "if sql = cache_get(:_#{type}_sql); return sql end" if cacheable 248 lines << 'check_delete_allowed!' << 'check_not_limited!(:delete)' if type == :delete 249 lines << 'sql = @opts[:append_sql] || sql_string_origin' 250 251 if clauses.all?{|c| c.is_a?(Array)} 252 clauses.each do |i, cs| 253 lines << i 254 lines.concat(clause_methods(type, cs).map{|x| "#{x}(sql)"}) 255 end 256 lines << 'end' 257 else 258 lines.concat(clause_methods(type, clauses).map{|x| "#{x}(sql)"}) 259 end 260 261 lines << "cache_set(:_#{type}_sql, sql) if cache_sql?" if cacheable 262 lines << 'sql' 263 lines << 'end' 264 265 mod.class_eval lines.join("\n"), __FILE__, __LINE__ 266 end
Define a dataset literalization method for the given type in the given module, using the given clauses.
Arguments:
- mod
-
Module in which to define method
- type
-
Type of
SQL
literalization method to create, either :select, :insert, :update, or :delete - clauses
-
array of clauses that make up the
SQL
query for the type. This can either be a single array of symbols/strings, or it can be an array of pairs, with the first element in each pair being an if/elsif/else code fragment, and the second element in each pair being an array of symbol/strings for the appropriate branch.
Public Instance Methods
Source
# File lib/sequel/dataset/sql.rb 300 def aliased_expression_sql_append(sql, ae) 301 literal_append(sql, ae.expression) 302 as_sql_append(sql, ae.alias, ae.columns) 303 end
Append literalization of aliased expression to SQL
string.
Source
# File lib/sequel/dataset/sql.rb 306 def array_sql_append(sql, a) 307 if a.empty? 308 sql << '(NULL)' 309 else 310 sql << '(' 311 expression_list_append(sql, a) 312 sql << ')' 313 end 314 end
Append literalization of array to SQL
string.
Source
# File lib/sequel/dataset/sql.rb 317 def boolean_constant_sql_append(sql, constant) 318 if (constant == true || constant == false) && !supports_where_true? 319 sql << (constant == true ? '(1 = 1)' : '(1 = 0)') 320 else 321 literal_append(sql, constant) 322 end 323 end
Append literalization of boolean constant to SQL
string.
Source
# File lib/sequel/dataset/sql.rb 326 def case_expression_sql_append(sql, ce) 327 sql << '(CASE' 328 if ce.expression? 329 sql << ' ' 330 literal_append(sql, ce.expression) 331 end 332 w = " WHEN " 333 t = " THEN " 334 ce.conditions.each do |c,r| 335 sql << w 336 literal_append(sql, c) 337 sql << t 338 literal_append(sql, r) 339 end 340 sql << " ELSE " 341 literal_append(sql, ce.default) 342 sql << " END)" 343 end
Append literalization of case expression to SQL
string.
Source
# File lib/sequel/dataset/sql.rb 346 def cast_sql_append(sql, expr, type) 347 sql << 'CAST(' 348 literal_append(sql, expr) 349 sql << ' AS ' << db.cast_type_literal(type).to_s 350 sql << ')' 351 end
Append literalization of cast expression to SQL
string.
Source
# File lib/sequel/dataset/sql.rb 354 def column_all_sql_append(sql, ca) 355 qualified_identifier_sql_append(sql, ca.table, WILDCARD) 356 end
Append literalization of column all selection to SQL
string.
Source
# File lib/sequel/dataset/sql.rb 359 def complex_expression_sql_append(sql, op, args) 360 case op 361 when *IS_OPERATORS 362 r = args[1] 363 if r.nil? || supports_is_true? 364 raise(InvalidOperation, 'Invalid argument used for IS operator') unless val = IS_LITERALS[r] 365 sql << '(' 366 literal_append(sql, args[0]) 367 sql << ' ' << op.to_s << ' ' 368 sql << val << ')' 369 elsif op == :IS 370 complex_expression_sql_append(sql, :"=", args) 371 else 372 complex_expression_sql_append(sql, :OR, [SQL::BooleanExpression.new(:"!=", *args), SQL::BooleanExpression.new(:IS, args[0], nil)]) 373 end 374 when :IN, :"NOT IN" 375 cols = args[0] 376 vals = args[1] 377 col_array = true if cols.is_a?(Array) 378 if vals.is_a?(Array) 379 val_array = true 380 empty_val_array = vals == [] 381 end 382 if empty_val_array 383 literal_append(sql, empty_array_value(op, cols)) 384 elsif col_array 385 if !supports_multiple_column_in? 386 if val_array 387 expr = SQL::BooleanExpression.new(:OR, *vals.to_a.map{|vs| SQL::BooleanExpression.from_value_pairs(cols.to_a.zip(vs).map{|c, v| [c, v]})}) 388 literal_append(sql, op == :IN ? expr : ~expr) 389 else 390 old_vals = vals 391 vals = vals.naked if vals.is_a?(Sequel::Dataset) 392 vals = vals.to_a 393 val_cols = old_vals.columns 394 complex_expression_sql_append(sql, op, [cols, vals.map!{|x| x.values_at(*val_cols)}]) 395 end 396 else 397 # If the columns and values are both arrays, use array_sql instead of 398 # literal so that if values is an array of two element arrays, it 399 # will be treated as a value list instead of a condition specifier. 400 sql << '(' 401 literal_append(sql, cols) 402 sql << ' ' << op.to_s << ' ' 403 if val_array 404 array_sql_append(sql, vals) 405 else 406 literal_append(sql, vals) 407 end 408 sql << ')' 409 end 410 else 411 sql << '(' 412 literal_append(sql, cols) 413 sql << ' ' << op.to_s << ' ' 414 literal_append(sql, vals) 415 sql << ')' 416 end 417 when :LIKE, :'NOT LIKE' 418 sql << '(' 419 literal_append(sql, args[0]) 420 sql << ' ' << op.to_s << ' ' 421 literal_append(sql, args[1]) 422 if requires_like_escape? 423 sql << " ESCAPE " 424 literal_append(sql, "\\") 425 end 426 sql << ')' 427 when :ILIKE, :'NOT ILIKE' 428 complex_expression_sql_append(sql, (op == :ILIKE ? :LIKE : :"NOT LIKE"), args.map{|v| Sequel.function(:UPPER, v)}) 429 when :** 430 function_sql_append(sql, Sequel.function(:power, *args)) 431 when *TWO_ARITY_OPERATORS 432 if REGEXP_OPERATORS.include?(op) && !supports_regexp? 433 raise InvalidOperation, "Pattern matching via regular expressions is not supported on #{db.database_type}" 434 end 435 sql << '(' 436 literal_append(sql, args[0]) 437 sql << ' ' << op.to_s << ' ' 438 literal_append(sql, args[1]) 439 sql << ')' 440 when *N_ARITY_OPERATORS 441 sql << '(' 442 c = false 443 op_str = " #{op} " 444 args.each do |a| 445 sql << op_str if c 446 literal_append(sql, a) 447 c ||= true 448 end 449 sql << ')' 450 when :NOT 451 sql << 'NOT ' 452 literal_append(sql, args[0]) 453 when :NOOP 454 literal_append(sql, args[0]) 455 when :'B~' 456 sql << '~' 457 literal_append(sql, args[0]) 458 when :extract 459 sql << 'extract(' << args[0].to_s << ' FROM ' 460 literal_append(sql, args[1]) 461 sql << ')' 462 else 463 raise(InvalidOperation, "invalid operator #{op}") 464 end 465 end
Append literalization of complex expression to SQL
string.
Source
# File lib/sequel/dataset/sql.rb 468 def constant_sql_append(sql, constant) 469 sql << constant.to_s 470 end
Append literalization of constant to SQL
string.
Source
# File lib/sequel/dataset/sql.rb 474 def delayed_evaluation_sql_append(sql, delay) 475 # Delayed evaluations are used specifically so the SQL 476 # can differ in subsequent calls, so we definitely don't 477 # want to cache the sql in this case. 478 disable_sql_caching! 479 480 if recorder = @opts[:placeholder_literalizer] 481 recorder.use(sql, lambda{delay.call(self)}, nil) 482 else 483 literal_append(sql, delay.call(self)) 484 end 485 end
Append literalization of delayed evaluation to SQL
string, causing the delayed evaluation proc to be evaluated.
Source
# File lib/sequel/dataset/sql.rb 488 def function_sql_append(sql, f) 489 name = f.name 490 opts = f.opts 491 492 if opts[:emulate] 493 if emulate_function?(name) 494 emulate_function_sql_append(sql, f) 495 return 496 end 497 498 name = native_function_name(name) 499 end 500 501 sql << 'LATERAL ' if opts[:lateral] 502 503 case name 504 when SQL::Identifier 505 if supports_quoted_function_names? && opts[:quoted] 506 literal_append(sql, name) 507 else 508 sql << name.value.to_s 509 end 510 when SQL::QualifiedIdentifier 511 if supports_quoted_function_names? && opts[:quoted] != false 512 literal_append(sql, name) 513 else 514 sql << split_qualifiers(name).join('.') 515 end 516 else 517 if supports_quoted_function_names? && opts[:quoted] 518 quote_identifier_append(sql, name) 519 else 520 sql << name.to_s 521 end 522 end 523 524 sql << '(' 525 if filter = opts[:filter] 526 filter = filter_expr(filter, &opts[:filter_block]) 527 end 528 if opts[:*] 529 if filter && !supports_filtered_aggregates? 530 literal_append(sql, Sequel.case({filter=>1}, nil)) 531 filter = nil 532 else 533 sql << '*' 534 end 535 else 536 sql << "DISTINCT " if opts[:distinct] 537 if filter && !supports_filtered_aggregates? 538 expression_list_append(sql, f.args.map{|arg| Sequel.case({filter=>arg}, nil)}) 539 filter = nil 540 else 541 expression_list_append(sql, f.args) 542 end 543 if order = opts[:order] 544 sql << " ORDER BY " 545 expression_list_append(sql, order) 546 end 547 end 548 sql << ')' 549 550 if group = opts[:within_group] 551 sql << " WITHIN GROUP (ORDER BY " 552 expression_list_append(sql, group) 553 sql << ')' 554 end 555 556 if filter 557 sql << " FILTER (WHERE " 558 literal_append(sql, filter) 559 sql << ')' 560 end 561 562 if window = opts[:over] 563 sql << ' OVER ' 564 window_sql_append(sql, window.opts) 565 end 566 567 if opts[:with_ordinality] 568 sql << " WITH ORDINALITY" 569 end 570 end
Append literalization of function call to SQL
string.
Source
# File lib/sequel/dataset/sql.rb 573 def join_clause_sql_append(sql, jc) 574 table = jc.table 575 table_alias = jc.table_alias 576 table_alias = nil if table == table_alias && !jc.column_aliases 577 sql << ' ' << join_type_sql(jc.join_type) << ' ' 578 identifier_append(sql, table) 579 as_sql_append(sql, table_alias, jc.column_aliases) if table_alias 580 end
Append literalization of JOIN clause without ON or USING to SQL
string.
Source
# File lib/sequel/dataset/sql.rb 583 def join_on_clause_sql_append(sql, jc) 584 join_clause_sql_append(sql, jc) 585 sql << ' ON ' 586 literal_append(sql, filter_expr(jc.on)) 587 end
Append literalization of JOIN ON clause to SQL
string.
Source
# File lib/sequel/dataset/sql.rb 590 def join_using_clause_sql_append(sql, jc) 591 join_clause_sql_append(sql, jc) 592 join_using_clause_using_sql_append(sql, jc.using) 593 end
Append literalization of JOIN USING clause to SQL
string.
Source
# File lib/sequel/dataset/sql.rb 596 def negative_boolean_constant_sql_append(sql, constant) 597 sql << 'NOT ' 598 boolean_constant_sql_append(sql, constant) 599 end
Append literalization of negative boolean constant to SQL
string.
Source
# File lib/sequel/dataset/sql.rb 602 def ordered_expression_sql_append(sql, oe) 603 if emulate = requires_emulating_nulls_first? 604 case oe.nulls 605 when :first 606 null_order = 0 607 when :last 608 null_order = 2 609 end 610 611 if null_order 612 literal_append(sql, Sequel.case({{oe.expression=>nil}=>null_order}, 1)) 613 sql << ", " 614 end 615 end 616 617 literal_append(sql, oe.expression) 618 sql << (oe.descending ? ' DESC' : ' ASC') 619 620 unless emulate 621 case oe.nulls 622 when :first 623 sql << " NULLS FIRST" 624 when :last 625 sql << " NULLS LAST" 626 end 627 end 628 end
Append literalization of ordered expression to SQL
string.
Source
# File lib/sequel/dataset/sql.rb 631 def placeholder_literal_string_sql_append(sql, pls) 632 args = pls.args 633 str = pls.str 634 sql << '(' if pls.parens 635 if args.is_a?(Hash) 636 if args.empty? 637 sql << str 638 else 639 re = /:(#{args.keys.map{|k| Regexp.escape(k.to_s)}.join('|')})\b/ 640 while true 641 previous, q, str = str.partition(re) 642 sql << previous 643 literal_append(sql, args[($1||q[1..-1].to_s).to_sym]) unless q.empty? 644 break if str.empty? 645 end 646 end 647 elsif str.is_a?(Array) 648 len = args.length 649 str.each_with_index do |s, i| 650 sql << s 651 literal_append(sql, args[i]) unless i == len 652 end 653 unless str.length == args.length || str.length == args.length + 1 654 raise Error, "Mismatched number of placeholders (#{str.length}) and placeholder arguments (#{args.length}) when using placeholder array" 655 end 656 else 657 i = -1 658 match_len = args.length - 1 659 while true 660 previous, q, str = str.partition('?') 661 sql << previous 662 literal_append(sql, args.at(i+=1)) unless q.empty? 663 if str.empty? 664 unless i == match_len 665 raise Error, "Mismatched number of placeholders (#{i+1}) and placeholder arguments (#{args.length}) when using placeholder string" 666 end 667 break 668 end 669 end 670 end 671 sql << ')' if pls.parens 672 end
Append literalization of placeholder literal string to SQL
string.
Source
# File lib/sequel/dataset/sql.rb 677 def qualified_identifier_sql_append(sql, table, column=(c = table.column; table = table.table; c)) 678 identifier_append(sql, table) 679 sql << '.' 680 identifier_append(sql, column) 681 end
Append literalization of qualified identifier to SQL
string. If 3 arguments are given, the 2nd should be the table/qualifier and the third should be column/qualified. If 2 arguments are given, the 2nd should be an SQL::QualifiedIdentifier
.
Source
# File lib/sequel/dataset/sql.rb 687 def quote_identifier_append(sql, name) 688 if name.is_a?(LiteralString) 689 sql << name 690 else 691 name = name.value if name.is_a?(SQL::Identifier) 692 name = input_identifier(name) 693 if quote_identifiers? 694 quoted_identifier_append(sql, name) 695 else 696 sql << name 697 end 698 end 699 end
Append literalization of unqualified identifier to SQL
string. Adds quoting to identifiers (columns and tables). If identifiers are not being quoted, returns name as a string. If identifiers are being quoted quote the name with quoted_identifier.
Source
# File lib/sequel/dataset/sql.rb 702 def quote_schema_table_append(sql, table) 703 schema, table = schema_and_table(table) 704 if schema 705 quote_identifier_append(sql, schema) 706 sql << '.' 707 end 708 quote_identifier_append(sql, table) 709 end
Append literalization of identifier or unqualified identifier to SQL
string.
Source
# File lib/sequel/dataset/sql.rb 715 def quoted_identifier_append(sql, name) 716 sql << '"' << name.to_s.gsub('"', '""') << '"' 717 end
Append literalization of quoted identifier to SQL
string. This method quotes the given name with the SQL
standard double quote. should be overridden by subclasses to provide quoting not matching the SQL
standard, such as backtick (used by MySQL
and SQLite
).
Source
# File lib/sequel/dataset/sql.rb 726 def schema_and_table(table_name, sch=nil) 727 sch = sch.to_s if sch 728 case table_name 729 when Symbol 730 s, t, _ = split_symbol(table_name) 731 [s||sch, t] 732 when SQL::QualifiedIdentifier 733 [table_name.table.to_s, table_name.column.to_s] 734 when SQL::Identifier 735 [sch, table_name.value.to_s] 736 when String 737 [sch, table_name] 738 else 739 raise Error, 'table_name should be a Symbol, SQL::QualifiedIdentifier, SQL::Identifier, or String' 740 end 741 end
Split the schema information from the table, returning two strings, one for the schema and one for the table. The returned schema may be nil, but the table will always have a string value.
Note that this function does not handle tables with more than one level of qualification (e.g. database.schema.table on Microsoft SQL
Server).
Source
# File lib/sequel/dataset/sql.rb 749 def split_qualifiers(table_name, *args) 750 case table_name 751 when SQL::QualifiedIdentifier 752 split_qualifiers(table_name.table, nil) + split_qualifiers(table_name.column, nil) 753 else 754 sch, table = schema_and_table(table_name, *args) 755 sch ? [sch, table] : [table] 756 end 757 end
Splits table_name into an array of strings.
ds.split_qualifiers(:s) # ['s'] ds.split_qualifiers(Sequel[:t][:s]) # ['t', 's'] ds.split_qualifiers(Sequel[:d][:t][:s]) # ['d', 't', 's'] ds.split_qualifiers(Sequel.qualify(Sequel[:h][:d], Sequel[:t][:s])) # ['h', 'd', 't', 's']
Source
# File lib/sequel/dataset/sql.rb 760 def subscript_sql_append(sql, s) 761 case s.expression 762 when Symbol, SQL::Subscript, SQL::Identifier, SQL::QualifiedIdentifier 763 # nothing 764 else 765 wrap_expression = true 766 sql << '(' 767 end 768 literal_append(sql, s.expression) 769 if wrap_expression 770 sql << ')[' 771 else 772 sql << '[' 773 end 774 sub = s.sub 775 if sub.length == 1 && (range = sub.first).is_a?(Range) 776 literal_append(sql, range.begin) 777 sql << ':' 778 e = range.end 779 e -= 1 if range.exclude_end? && e.is_a?(Integer) 780 literal_append(sql, e) 781 else 782 expression_list_append(sql, s.sub) 783 end 784 sql << ']' 785 end
Append literalization of subscripts (SQL
array accesses) to SQL
string.
Source
# File lib/sequel/dataset/sql.rb 788 def window_sql_append(sql, opts) 789 raise(Error, 'This dataset does not support window functions') unless supports_window_functions? 790 space = false 791 space_s = ' ' 792 793 sql << '(' 794 795 if window = opts[:window] 796 literal_append(sql, window) 797 space = true 798 end 799 800 if part = opts[:partition] 801 sql << space_s if space 802 sql << "PARTITION BY " 803 expression_list_append(sql, Array(part)) 804 space = true 805 end 806 807 if order = opts[:order] 808 sql << space_s if space 809 sql << "ORDER BY " 810 expression_list_append(sql, Array(order)) 811 space = true 812 end 813 814 if frame = opts[:frame] 815 sql << space_s if space 816 817 if frame.is_a?(String) 818 sql << frame 819 else 820 case frame 821 when :all 822 frame_type = :rows 823 frame_start = :preceding 824 frame_end = :following 825 when :rows, :range, :groups 826 frame_type = frame 827 frame_start = :preceding 828 frame_end = :current 829 when Hash 830 frame_type = frame[:type] 831 unless frame_type == :rows || frame_type == :range || frame_type == :groups 832 raise Error, "invalid window :frame :type option: #{frame_type.inspect}" 833 end 834 unless frame_start = frame[:start] 835 raise Error, "invalid window :frame :start option: #{frame_start.inspect}" 836 end 837 frame_end = frame[:end] 838 frame_exclude = frame[:exclude] 839 else 840 raise Error, "invalid window :frame option: #{frame.inspect}" 841 end 842 843 sql << frame_type.to_s.upcase << " " 844 sql << 'BETWEEN ' if frame_end 845 window_frame_boundary_sql_append(sql, frame_start, :preceding) 846 if frame_end 847 sql << " AND " 848 window_frame_boundary_sql_append(sql, frame_end, :following) 849 end 850 851 if frame_exclude 852 sql << " EXCLUDE " 853 854 case frame_exclude 855 when :current 856 sql << "CURRENT ROW" 857 when :group 858 sql << "GROUP" 859 when :ties 860 sql << "TIES" 861 when :no_others 862 sql << "NO OTHERS" 863 else 864 raise Error, "invalid window :frame :exclude option: #{frame_exclude.inspect}" 865 end 866 end 867 end 868 end 869 870 sql << ')' 871 end
Append literalization of windows (for window functions) to SQL
string.
Protected Instance Methods
Source
# File lib/sequel/dataset/sql.rb 877 def compound_from_self 878 (@opts[:sql] || @opts[:limit] || @opts[:order] || @opts[:offset]) ? from_self : self 879 end
Return a from_self
dataset if an order or limit is specified, so it works as expected with UNION, EXCEPT, and INTERSECT clauses.
Private Instance Methods
Source
# File lib/sequel/dataset/sql.rb 1071 def _check_modification_allowed!(modifying_joins_supported) 1072 raise(InvalidOperation, "Grouped datasets cannot be modified") if opts[:group] 1073 raise(InvalidOperation, "Joined datasets cannot be modified") if !modifying_joins_supported && joined_dataset? 1074 end
Internals of the check_*_allowed! methods
Source
# File lib/sequel/dataset/sql.rb 1281 def _insert_columns_sql(sql, columns) 1282 if columns && !columns.empty? 1283 sql << ' (' 1284 identifier_list_append(sql, columns) 1285 sql << ')' 1286 end 1287 end
Source
# File lib/sequel/dataset/sql.rb 1303 def _insert_values_sql(sql, values) 1304 case values 1305 when Array 1306 if values.empty? 1307 sql << " DEFAULT VALUES" 1308 else 1309 sql << " VALUES " 1310 literal_append(sql, values) 1311 end 1312 when Dataset 1313 sql << ' ' 1314 subselect_sql_append(sql, values) 1315 when LiteralString 1316 sql << ' ' << values 1317 else 1318 raise Error, "Unsupported INSERT values type, should be an Array or Dataset: #{values.inspect}" 1319 end 1320 end
Source
# File lib/sequel/dataset/sql.rb 896 def _merge_delete_sql(sql, data) 897 sql << " THEN DELETE" 898 end
Source
# File lib/sequel/dataset/sql.rb 884 def _merge_insert_sql(sql, data) 885 sql << " THEN INSERT" 886 columns, values = _parse_insert_sql_args(data[:values]) 887 _insert_columns_sql(sql, columns) 888 _insert_values_sql(sql, values) 889 end
Append the INSERT sql used in a MERGE
Source
# File lib/sequel/dataset/sql.rb 891 def _merge_update_sql(sql, data) 892 sql << " THEN UPDATE SET " 893 update_sql_values_hash(sql, data[:values]) 894 end
Source
# File lib/sequel/dataset/sql.rb 935 def _merge_when_conditions_sql(sql, data) 936 if data.has_key?(:conditions) 937 sql << " AND " 938 literal_append(sql, data[:conditions]) 939 end 940 end
Append MERGE WHEN conditions, if there are conditions provided.
Source
# File lib/sequel/dataset/sql.rb 923 def _merge_when_sql(sql) 924 raise Error, "no WHEN [NOT] MATCHED clauses provided for MERGE" unless merge_when = @opts[:merge_when] 925 merge_when.each do |data| 926 type = data[:type] 927 sql << MERGE_TYPE_SQL[type] 928 type = MERGE_NORMALIZE_TYPE_MAP[type] || type 929 _merge_when_conditions_sql(sql, data) 930 send(:"_merge_#{type}_sql", sql, data) 931 end 932 end
Add the WHEN clauses to the MERGE SQL
Source
# File lib/sequel/dataset/sql.rb 946 def _parse_insert_sql_args(values) 947 columns = [] 948 949 case values.size 950 when 0 951 values = [] 952 when 1 953 case vals = values[0] 954 when Hash 955 values = [] 956 vals.each do |k,v| 957 columns << k 958 values << v 959 end 960 when Dataset, Array, LiteralString 961 values = vals 962 end 963 when 2 964 if (v0 = values[0]).is_a?(Array) && ((v1 = values[1]).is_a?(Array) || v1.is_a?(Dataset) || v1.is_a?(LiteralString)) 965 columns, values = v0, v1 966 raise(Error, "Different number of values and columns given to insert_sql") if values.is_a?(Array) and columns.length != values.length 967 end 968 end 969 970 [columns, values] 971 end
Parse the values passed to insert_sql
, returning columns and values to use for the INSERT. Returned columns is always an array, but can be empty for an INSERT without explicit column references. Returned values can be an array, dataset, or literal string.
Source
# File lib/sequel/dataset/sql.rb 975 def _truncate_sql(table) 976 "TRUNCATE TABLE #{table}" 977 end
Formats the truncate statement. Assumes the table given has already been literalized.
Source
# File lib/sequel/dataset/sql.rb 1024 def aggreate_dataset_use_from_self? 1025 options_overlap(COUNT_FROM_SELF_OPTS) 1026 end
Whether to use from_self
for an aggregate dataset.
Source
# File lib/sequel/dataset/sql.rb 1019 def aggregate_dataset 1020 (aggreate_dataset_use_from_self? ? from_self : unordered).naked 1021 end
Clone of this dataset usable in aggregate operations. Does a from_self
if dataset contains any parameters that would affect normal aggregation, or just removes an existing order if not. Also removes the row_proc
, which isn’t needed for aggregate calculations.
Source
# File lib/sequel/dataset/sql.rb 980 def alias_alias_symbol(s) 981 case s 982 when Symbol 983 s 984 when String 985 s.to_sym 986 when SQL::Identifier 987 s.value.to_s.to_sym 988 else 989 raise Error, "Invalid alias for alias_alias_symbol: #{s.inspect}" 990 end 991 end
Returns an appropriate symbol for the alias represented by s.
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# File lib/sequel/dataset/sql.rb 996 def alias_symbol(sym) 997 case sym 998 when Symbol 999 s, t, a = split_symbol(sym) 1000 a || s ? (a || t).to_sym : sym 1001 when String 1002 sym.to_sym 1003 when SQL::Identifier 1004 sym.value.to_s.to_sym 1005 when SQL::QualifiedIdentifier 1006 alias_symbol(sym.column) 1007 when SQL::AliasedExpression 1008 alias_alias_symbol(sym.alias) 1009 else 1010 raise Error, "Invalid alias for alias_symbol: #{sym.inspect}" 1011 end 1012 end
Returns an appropriate alias symbol for the given object, which can be a Symbol
, String
, SQL::Identifier
, SQL::QualifiedIdentifier
, or SQL::AliasedExpression
.
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# File lib/sequel/dataset/sql.rb 1029 def as_sql_append(sql, aliaz, column_aliases=nil) 1030 sql << ' AS ' 1031 quote_identifier_append(sql, aliaz) 1032 if column_aliases 1033 raise Error, "#{db.database_type} does not support derived column lists" unless supports_derived_column_lists? 1034 sql << '(' 1035 identifier_list_append(sql, column_aliases) 1036 sql << ')' 1037 end 1038 end
Append aliasing expression to SQL
string.
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# File lib/sequel/dataset/sql.rb 1041 def cache_sql? 1042 !@opts[:no_cache_sql] && !cache_get(:_no_cache_sql) 1043 end
Don’t allow caching SQL
if specifically marked not to.
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# File lib/sequel/dataset/sql.rb 1061 def check_delete_allowed! 1062 _check_modification_allowed!(supports_deleting_joins?) 1063 end
Check whether it is allowed to delete from this dataset.
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# File lib/sequel/dataset/sql.rb 1055 def check_insert_allowed! 1056 _check_modification_allowed!(false) 1057 end
Check whether it is allowed to insert into this dataset.
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# File lib/sequel/dataset/sql.rb 1048 def check_modification_allowed! 1049 # SEQUEL6: Remove 1050 Sequel::Deprecation.deprecate("Dataset#check_modification_allowed!", "Use check_{insert,delete,update,truncation}_allowed! instead") 1051 _check_modification_allowed!(supports_modifying_joins?) 1052 end
Raise an InvalidOperation exception if modification is not allowed for this dataset. Check whether it is allowed to insert into this dataset. Only for backwards compatibility with older external adapters.
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# File lib/sequel/dataset/sql.rb 1077 def check_not_limited!(type) 1078 return if @opts[:skip_limit_check] && type != :truncate 1079 raise InvalidOperation, "Dataset##{type} not supported on datasets with limits or offsets" if opts[:limit] || opts[:offset] 1080 end
Raise error if the dataset uses limits or offsets.
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# File lib/sequel/dataset/sql.rb 1066 def check_update_allowed! 1067 _check_modification_allowed!(supports_updating_joins?) 1068 end
Check whether it is allowed to update this dataset.
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# File lib/sequel/dataset/sql.rb 1084 def column_list_append(sql, columns) 1085 if (columns.nil? || columns.empty?) 1086 sql << '*' 1087 else 1088 expression_list_append(sql, columns) 1089 end 1090 end
Append column list to SQL
string. If the column list is empty, a wildcard (*) is appended.
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# File lib/sequel/dataset/sql.rb 1096 def complex_expression_arg_pairs(args) 1097 case args.length 1098 when 1 1099 args[0] 1100 when 2 1101 yield args[0], args[1] 1102 else 1103 args.inject{|m, a| yield(m, a)} 1104 end 1105 end
Yield each pair of arguments to the block, which should return an object representing the SQL
expression for those two arguments. For more than two arguments, the first argument to the block will be result of the previous block call.
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# File lib/sequel/dataset/sql.rb 1110 def complex_expression_arg_pairs_append(sql, args, &block) 1111 literal_append(sql, complex_expression_arg_pairs(args, &block)) 1112 end
Append the literalization of the args using complex_expression_arg_pairs
to the given SQL
string, used when database operator/function is 2-ary where Sequel
expression is N-ary.
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# File lib/sequel/dataset/sql.rb 1117 def complex_expression_emulate_append(sql, op, args) 1118 # :nocov: 1119 case op 1120 # :nocov: 1121 when :% 1122 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.function(:MOD, a, b)} 1123 when :>> 1124 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel./(a, Sequel.function(:power, 2, b))} 1125 when :<< 1126 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.*(a, Sequel.function(:power, 2, b))} 1127 when :&, :|, :^ 1128 f = BITWISE_METHOD_MAP[op] 1129 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.function(f, a, b)} 1130 when :'B~' 1131 sql << "((0 - " 1132 literal_append(sql, args[0]) 1133 sql << ") - 1)" 1134 end 1135 end
Append literalization of complex expression to SQL
string, for operators unsupported by some databases. Used by adapters for databases that don’t support the operators natively.
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# File lib/sequel/dataset/sql.rb 1138 def compound_dataset_sql_append(sql, ds) 1139 subselect_sql_append(sql, ds) 1140 end
Append literalization of dataset used in UNION/INTERSECT/EXCEPT clause to SQL
string.
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# File lib/sequel/dataset/sql.rb 1143 def dataset_alias(number) 1144 :"t#{number}" 1145 end
The alias to use for datasets, takes a number to make sure the name is unique.
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# File lib/sequel/dataset/sql.rb 1148 def default_time_format 1149 "'%H:%M:%S.%6N'" 1150 end
The strftime format to use when literalizing time (Sequel::SQLTime
) values.
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# File lib/sequel/dataset/sql.rb 1153 def default_timestamp_format 1154 "'%Y-%m-%d %H:%M:%S.%6N'" 1155 end
The strftime format to use when literalizing timestamp (Time/DateTime) values.
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# File lib/sequel/dataset/sql.rb 1157 def delete_delete_sql(sql) 1158 sql << 'DELETE' 1159 end
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# File lib/sequel/dataset/sql.rb 1161 def delete_from_sql(sql) 1162 if f = @opts[:from] 1163 sql << ' FROM ' 1164 source_list_append(sql, f) 1165 end 1166 end
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# File lib/sequel/dataset/sql.rb 1169 def disable_sql_caching! 1170 cache_set(:_no_cache_sql, true) 1171 end
Disable caching of SQL
for the current dataset
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# File lib/sequel/dataset/sql.rb 1213 def empty_array_value(op, cols) 1214 {1 => ((op == :IN) ? 0 : 1)} 1215 end
An expression for how to handle an empty array lookup.
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# File lib/sequel/dataset/sql.rb 1175 def empty_from_sql 1176 nil 1177 end
An SQL
FROM clause to use in SELECT statements where the dataset has no from tables.
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# File lib/sequel/dataset/sql.rb 1181 def emulate_function?(name) 1182 false 1183 end
Whether to emulate the function with the given name. This should only be true if the emulation goes beyond choosing a function with a different name.
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# File lib/sequel/dataset/sql.rb 1187 def expression_list_append(sql, columns) 1188 c = false 1189 co = ', ' 1190 columns.each do |col| 1191 sql << co if c 1192 literal_append(sql, col) 1193 c ||= true 1194 end 1195 end
Append literalization of array of expressions to SQL
string, separating them with commas.
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# File lib/sequel/dataset/sql.rb 1218 def format_timestamp(v) 1219 db.from_application_timestamp(v).strftime(default_timestamp_format) 1220 end
Format the timestamp based on the default_timestamp_format.
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# File lib/sequel/dataset/sql.rb 1226 def format_timestamp_usec(usec, ts=timestamp_precision) 1227 # SEQUEL6: Remove 1228 unless ts == 6 1229 usec = usec/(10 ** (6 - ts)) 1230 end 1231 sprintf(".%0#{ts}d", usec) 1232 end
Return the SQL
timestamp fragment to use for the fractional time part. Should start with the decimal point. Uses 6 decimal places by default.
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# File lib/sequel/dataset/sql.rb 1198 def grouping_element_list_append(sql, columns) 1199 c = false 1200 co = ', ' 1201 columns.each do |col| 1202 sql << co if c 1203 if col.is_a?(Array) && col.empty? 1204 sql << '()' 1205 else 1206 literal_append(sql, Array(col)) 1207 end 1208 c ||= true 1209 end 1210 end
Append literalization of array of grouping elements to SQL
string, seperating them with commas.
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# File lib/sequel/dataset/sql.rb 1237 def identifier_append(sql, v) 1238 if v.is_a?(String) 1239 case v 1240 when LiteralString 1241 sql << v 1242 when SQL::Blob 1243 literal_append(sql, v) 1244 else 1245 quote_identifier_append(sql, v) 1246 end 1247 else 1248 literal_append(sql, v) 1249 end 1250 end
Append literalization of identifier to SQL
string, considering regular strings as SQL
identifiers instead of SQL
strings.
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# File lib/sequel/dataset/sql.rb 1253 def identifier_list_append(sql, args) 1254 c = false 1255 comma = ', ' 1256 args.each do |a| 1257 sql << comma if c 1258 identifier_append(sql, a) 1259 c ||= true 1260 end 1261 end
Append literalization of array of identifiers to SQL
string.
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# File lib/sequel/dataset/sql.rb 1264 def input_identifier(v) 1265 v.to_s.upcase 1266 end
Upcase identifiers by default when inputting them into the database.
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# File lib/sequel/dataset/sql.rb 1277 def insert_columns_sql(sql) 1278 _insert_columns_sql(sql, opts[:columns]) 1279 end
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# File lib/sequel/dataset/sql.rb 1291 def insert_empty_columns_values 1292 [[columns.last], [DEFAULT]] 1293 end
The columns and values to use for an empty insert if the database doesn’t support INSERT with DEFAULT
VALUES.
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# File lib/sequel/dataset/sql.rb 1295 def insert_insert_sql(sql) 1296 sql << "INSERT" 1297 end
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# File lib/sequel/dataset/sql.rb 1268 def insert_into_sql(sql) 1269 sql << " INTO " 1270 if (f = @opts[:from]) && f.length == 1 1271 identifier_append(sql, unaliased_identifier(f.first)) 1272 else 1273 source_list_append(sql, f) 1274 end 1275 end
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# File lib/sequel/dataset/sql.rb 1322 def insert_returning_sql(sql) 1323 if opts.has_key?(:returning) 1324 sql << " RETURNING " 1325 column_list_append(sql, Array(opts[:returning])) 1326 end 1327 end
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# File lib/sequel/dataset/sql.rb 1299 def insert_values_sql(sql) 1300 _insert_values_sql(sql, opts[:values]) 1301 end
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# File lib/sequel/dataset/sql.rb 1333 def join_type_sql(join_type) 1334 "#{join_type.to_s.gsub('_', ' ').upcase} JOIN" 1335 end
SQL
fragment specifying a JOIN type, converts underscores to spaces and upcases.
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# File lib/sequel/dataset/sql.rb 1338 def join_using_clause_using_sql_append(sql, using_columns) 1339 sql << ' USING (' 1340 column_list_append(sql, using_columns) 1341 sql << ')' 1342 end
Append USING clause for JOIN USING
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# File lib/sequel/dataset/sql.rb 1346 def literal_array_append(sql, v) 1347 if Sequel.condition_specifier?(v) 1348 literal_expression_append(sql, SQL::BooleanExpression.from_value_pairs(v)) 1349 else 1350 array_sql_append(sql, v) 1351 end 1352 end
Append a literalization of the array to SQL
string. Treats as an expression if an array of all two pairs, or as a SQL
array otherwise.
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# File lib/sequel/dataset/sql.rb 1355 def literal_big_decimal(v) 1356 d = v.to_s("F") 1357 v.nan? || v.infinite? ? "'#{d}'" : d 1358 end
SQL
fragment for BigDecimal
Source
Source
# File lib/sequel/dataset/sql.rb 1366 def literal_dataset_append(sql, v) 1367 sql << 'LATERAL ' if v.opts[:lateral] 1368 sql << '(' 1369 subselect_sql_append(sql, v) 1370 sql << ')' 1371 end
Append literalization of dataset to SQL
string. Does a subselect inside parantheses.
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# File lib/sequel/dataset/sql.rb 1374 def literal_date(v) 1375 v.strftime("'%Y-%m-%d'") 1376 end
SQL
fragment for Date, using the ISO8601 format.
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# File lib/sequel/dataset/sql.rb 1379 def literal_date_append(sql, v) 1380 sql << literal_date(v) 1381 end
Append literalization of date to SQL
string.
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# File lib/sequel/dataset/sql.rb 1384 def literal_datetime(v) 1385 format_timestamp(v) 1386 end
SQL
fragment for DateTime
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# File lib/sequel/dataset/sql.rb 1389 def literal_datetime_append(sql, v) 1390 sql << literal_datetime(v) 1391 end
Append literalization of DateTime to SQL
string.
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# File lib/sequel/dataset/sql.rb 1394 def literal_expression_append(sql, v) 1395 v.to_s_append(self, sql) 1396 end
Append literalization of SQL::Expression
to SQL
string.
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# File lib/sequel/dataset/sql.rb 1399 def literal_false 1400 "'f'" 1401 end
SQL
fragment for false
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# File lib/sequel/dataset/sql.rb 1404 def literal_float(v) 1405 v.to_s 1406 end
SQL
fragment for Float
Source
Source
# File lib/sequel/dataset/sql.rb 1414 def literal_integer(v) 1415 v.to_s 1416 end
SQL
fragment for Integer
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# File lib/sequel/dataset/sql.rb 1419 def literal_nil 1420 "NULL" 1421 end
SQL
fragment for nil
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# File lib/sequel/dataset/sql.rb 1427 def literal_other_append(sql, v) 1428 # We can't be sure if v will always literalize to the same SQL, so 1429 # don't cache SQL for a dataset that uses this. 1430 disable_sql_caching! 1431 1432 if v.respond_to?(:sql_literal_append) 1433 v.sql_literal_append(self, sql) 1434 elsif v.respond_to?(:sql_literal) 1435 sql << v.sql_literal(self) 1436 else 1437 raise Error, "can't express #{v.inspect} as a SQL literal" 1438 end 1439 end
Append a literalization of the object to the given SQL
string. Calls sql_literal_append
if object responds to it, otherwise calls sql_literal
if object responds to it, otherwise raises an error. If a database specific type is allowed, this should be overriden in a subclass.
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# File lib/sequel/dataset/sql.rb 1442 def literal_sqltime(v) 1443 v.strftime(default_time_format) 1444 end
SQL
fragment for Sequel::SQLTime
, containing just the time part
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# File lib/sequel/dataset/sql.rb 1447 def literal_sqltime_append(sql, v) 1448 sql << literal_sqltime(v) 1449 end
Append literalization of Sequel::SQLTime
to SQL
string.
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# File lib/sequel/dataset/sql.rb 1452 def literal_string_append(sql, v) 1453 sql << "'" << v.gsub("'", "''") << "'" 1454 end
Append literalization of string to SQL
string.
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# File lib/sequel/dataset/sql.rb 1457 def literal_symbol_append(sql, v) 1458 c_table, column, c_alias = split_symbol(v) 1459 if c_table 1460 quote_identifier_append(sql, c_table) 1461 sql << '.' 1462 end 1463 quote_identifier_append(sql, column) 1464 as_sql_append(sql, c_alias) if c_alias 1465 end
Append literalization of symbol to SQL
string.
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# File lib/sequel/dataset/sql.rb 1468 def literal_time(v) 1469 format_timestamp(v) 1470 end
SQL
fragment for Time
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# File lib/sequel/dataset/sql.rb 1473 def literal_time_append(sql, v) 1474 sql << literal_time(v) 1475 end
Append literalization of Time to SQL
string.
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# File lib/sequel/dataset/sql.rb 1478 def literal_true 1479 "'t'" 1480 end
SQL
fragment for true
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# File lib/sequel/dataset/sql.rb 1486 def multi_insert_sql_strategy 1487 :separate 1488 end
What strategy to use for import/multi_insert. While SQL-92 defaults to allowing multiple rows in a VALUES clause, there are enough databases that don’t allow that that it can’t be the default. Use separate queries by default, which works everywhere.
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# File lib/sequel/dataset/sql.rb 1492 def native_function_name(emulated_function) 1493 emulated_function 1494 end
Get the native function name given the emulated function name.
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# File lib/sequel/dataset/sql.rb 1498 def qualified_column_name(column, table) 1499 if column.is_a?(Symbol) 1500 c_table, column, _ = split_symbol(column) 1501 unless c_table 1502 case table 1503 when Symbol 1504 schema, table, t_alias = split_symbol(table) 1505 t_alias ||= Sequel::SQL::QualifiedIdentifier.new(schema, table) if schema 1506 when Sequel::SQL::AliasedExpression 1507 t_alias = table.alias 1508 end 1509 c_table = t_alias || table 1510 end 1511 ::Sequel::SQL::QualifiedIdentifier.new(c_table, column) 1512 else 1513 column 1514 end 1515 end
Returns a qualified column name (including a table name) if the column name isn’t already qualified.
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# File lib/sequel/dataset/sql.rb 1518 def qualified_expression(e, table) 1519 Qualifier.new(table).transform(e) 1520 end
Qualify the given expression to the given table.
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# File lib/sequel/dataset/sql.rb 1522 def select_columns_sql(sql) 1523 sql << ' ' 1524 column_list_append(sql, @opts[:select]) 1525 end
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# File lib/sequel/dataset/sql.rb 1541 def select_compounds_sql(sql) 1542 return unless c = @opts[:compounds] 1543 c.each do |type, dataset, all| 1544 sql << ' ' << type.to_s.upcase 1545 sql << ' ALL' if all 1546 sql << ' ' 1547 compound_dataset_sql_append(sql, dataset) 1548 end 1549 end
Modify the sql to add a dataset to the via an EXCEPT, INTERSECT, or UNION clause. This uses a subselect for the compound datasets used, because using parantheses doesn’t work on all databases.
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# File lib/sequel/dataset/sql.rb 1527 def select_distinct_sql(sql) 1528 if distinct = @opts[:distinct] 1529 sql << " DISTINCT" 1530 unless distinct.empty? 1531 sql << " ON (" 1532 expression_list_append(sql, distinct) 1533 sql << ')' 1534 end 1535 end 1536 end
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# File lib/sequel/dataset/sql.rb 1551 def select_from_sql(sql) 1552 if f = @opts[:from] 1553 sql << ' FROM ' 1554 source_list_append(sql, f) 1555 elsif f = empty_from_sql 1556 sql << f 1557 end 1558 end
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# File lib/sequel/dataset/sql.rb 1560 def select_group_sql(sql) 1561 if group = @opts[:group] 1562 sql << " GROUP BY " 1563 if go = @opts[:group_options] 1564 if go == :"grouping sets" 1565 sql << go.to_s.upcase << '(' 1566 grouping_element_list_append(sql, group) 1567 sql << ')' 1568 elsif uses_with_rollup? 1569 expression_list_append(sql, group) 1570 sql << " WITH " << go.to_s.upcase 1571 else 1572 sql << go.to_s.upcase << '(' 1573 expression_list_append(sql, group) 1574 sql << ')' 1575 end 1576 else 1577 expression_list_append(sql, group) 1578 end 1579 end 1580 end
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# File lib/sequel/dataset/sql.rb 1582 def select_having_sql(sql) 1583 if having = @opts[:having] 1584 sql << " HAVING " 1585 literal_append(sql, having) 1586 end 1587 end
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# File lib/sequel/dataset/sql.rb 1589 def select_join_sql(sql) 1590 if js = @opts[:join] 1591 js.each{|j| literal_append(sql, j)} 1592 end 1593 end
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# File lib/sequel/dataset/sql.rb 1595 def select_limit_sql(sql) 1596 if l = @opts[:limit] 1597 sql << " LIMIT " 1598 literal_append(sql, l) 1599 if o = @opts[:offset] 1600 sql << " OFFSET " 1601 literal_append(sql, o) 1602 end 1603 elsif @opts[:offset] 1604 select_only_offset_sql(sql) 1605 end 1606 end
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# File lib/sequel/dataset/sql.rb 1608 def select_lock_sql(sql) 1609 case l = @opts[:lock] 1610 when :update 1611 sql << ' FOR UPDATE' 1612 when String 1613 sql << ' ' << l 1614 end 1615 end
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# File lib/sequel/dataset/sql.rb 1620 def select_only_offset_sql(sql) 1621 sql << " OFFSET " 1622 literal_append(sql, @opts[:offset]) 1623 end
Used only if there is an offset and no limit, making it easier to override in the adapter, as many databases do not support just a plain offset with no limit.
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# File lib/sequel/dataset/sql.rb 1625 def select_order_sql(sql) 1626 if o = @opts[:order] 1627 sql << " ORDER BY " 1628 expression_list_append(sql, o) 1629 end 1630 end
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# File lib/sequel/dataset/sql.rb 1634 def select_select_sql(sql) 1635 sql << 'SELECT' 1636 end
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# File lib/sequel/dataset/sql.rb 1638 def select_where_sql(sql) 1639 if w = @opts[:where] 1640 sql << " WHERE " 1641 literal_append(sql, w) 1642 end 1643 end
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# File lib/sequel/dataset/sql.rb 1647 def select_window_sql(sql) 1648 if ws = @opts[:window] 1649 sql << " WINDOW " 1650 c = false 1651 co = ', ' 1652 as = ' AS ' 1653 ws.map do |name, window| 1654 sql << co if c 1655 literal_append(sql, name) 1656 sql << as 1657 literal_append(sql, window) 1658 c ||= true 1659 end 1660 end 1661 end
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# File lib/sequel/dataset/sql.rb 1663 def select_with_sql(sql) 1664 return unless supports_cte? 1665 ctes = opts[:with] 1666 return if !ctes || ctes.empty? 1667 sql << select_with_sql_base 1668 c = false 1669 comma = ', ' 1670 ctes.each do |cte| 1671 sql << comma if c 1672 select_with_sql_cte(sql, cte) 1673 c ||= true 1674 end 1675 sql << ' ' 1676 end
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# File lib/sequel/dataset/sql.rb 1681 def select_with_sql_base 1682 "WITH " 1683 end
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# File lib/sequel/dataset/sql.rb 1685 def select_with_sql_cte(sql, cte) 1686 select_with_sql_prefix(sql, cte) 1687 literal_dataset_append(sql, cte[:dataset]) 1688 end
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# File lib/sequel/dataset/sql.rb 1690 def select_with_sql_prefix(sql, w) 1691 quote_identifier_append(sql, w[:name]) 1692 if args = w[:args] 1693 sql << '(' 1694 identifier_list_append(sql, args) 1695 sql << ')' 1696 end 1697 sql << ' AS ' 1698 1699 case w[:materialized] 1700 when true 1701 sql << "MATERIALIZED " 1702 when false 1703 sql << "NOT MATERIALIZED " 1704 end 1705 end
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# File lib/sequel/dataset/sql.rb 1708 def skip_symbol_cache? 1709 @opts[:skip_symbol_cache] 1710 end
Whether the symbol cache should be skipped when literalizing the dataset
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# File lib/sequel/dataset/sql.rb 1714 def source_list_append(sql, sources) 1715 raise(Error, 'No source specified for query') if sources.nil? || sources == [] 1716 identifier_list_append(sql, sources) 1717 end
Append literalization of array of sources/tables to SQL
string, raising an Error
if there are no sources.
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# File lib/sequel/dataset/sql.rb 1720 def split_symbol(sym) 1721 Sequel.split_symbol(sym) 1722 end
Delegate to Sequel.split_symbol.
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# File lib/sequel/dataset/sql.rb 1726 def sql_string_origin 1727 String.new 1728 end
The string that is appended to to create the SQL
query, the empty string by default.
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# File lib/sequel/dataset/sql.rb 1732 def sqltime_precision 1733 timestamp_precision 1734 end
The precision to use for SQLTime
instances (time column values without dates). Defaults to timestamp_precision.
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# File lib/sequel/dataset/sql.rb 1740 def static_sql(sql) 1741 if append_sql = @opts[:append_sql] 1742 if sql.is_a?(String) 1743 append_sql << sql 1744 else 1745 literal_append(append_sql, sql) 1746 end 1747 else 1748 if sql.is_a?(String) 1749 sql 1750 else 1751 literal(sql) 1752 end 1753 end 1754 end
SQL
to use if this dataset uses static SQL
. Since static SQL
can be a PlaceholderLiteralString in addition to a String
, we literalize nonstrings. If there is an append_sql for this dataset, append to that SQL
instead of returning the value.
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# File lib/sequel/dataset/sql.rb 1757 def subselect_sql_append(sql, ds) 1758 sds = subselect_sql_dataset(sql, ds) 1759 subselect_sql_append_sql(sql, sds) 1760 unless sds.send(:cache_sql?) 1761 # If subquery dataset does not allow caching SQL, 1762 # then this dataset should not allow caching SQL. 1763 disable_sql_caching! 1764 end 1765 end
Append literalization of the subselect to SQL
string.
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# File lib/sequel/dataset/sql.rb 1771 def subselect_sql_append_sql(sql, ds) 1772 ds.sql 1773 end
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# File lib/sequel/dataset/sql.rb 1767 def subselect_sql_dataset(sql, ds) 1768 ds.clone(:append_sql=>sql) 1769 end
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# File lib/sequel/dataset/sql.rb 1776 def timestamp_precision 1777 supports_timestamp_usecs? ? 6 : 0 1778 end
The number of decimal digits of precision to use in timestamps.
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# File lib/sequel/dataset/sql.rb 1786 def update_set_sql(sql) 1787 sql << ' SET ' 1788 values = @opts[:values] 1789 if values.is_a?(Hash) 1790 update_sql_values_hash(sql, values) 1791 else 1792 sql << values 1793 end 1794 end
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# File lib/sequel/dataset/sql.rb 1796 def update_sql_values_hash(sql, values) 1797 c = false 1798 eq = ' = ' 1799 values.each do |k, v| 1800 sql << ', ' if c 1801 if k.is_a?(String) && !k.is_a?(LiteralString) 1802 quote_identifier_append(sql, k) 1803 else 1804 literal_append(sql, k) 1805 end 1806 sql << eq 1807 literal_append(sql, v) 1808 c ||= true 1809 end 1810 end
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# File lib/sequel/dataset/sql.rb 1780 def update_table_sql(sql) 1781 sql << ' ' 1782 source_list_append(sql, @opts[:from]) 1783 select_join_sql(sql) if supports_modifying_joins? 1784 end
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# File lib/sequel/dataset/sql.rb 1812 def update_update_sql(sql) 1813 sql << 'UPDATE' 1814 end
Source
# File lib/sequel/dataset/sql.rb 1816 def window_frame_boundary_sql_append(sql, boundary, direction) 1817 case boundary 1818 when :current 1819 sql << "CURRENT ROW" 1820 when :preceding 1821 sql << "UNBOUNDED PRECEDING" 1822 when :following 1823 sql << "UNBOUNDED FOLLOWING" 1824 else 1825 if boundary.is_a?(Array) 1826 offset, direction = boundary 1827 unless boundary.length == 2 && (direction == :preceding || direction == :following) 1828 raise Error, "invalid window :frame boundary (:start or :end) option: #{boundary.inspect}" 1829 end 1830 else 1831 offset = boundary 1832 end 1833 1834 case offset 1835 when Numeric, String, SQL::Cast 1836 # nothing 1837 else 1838 raise Error, "invalid window :frame boundary (:start or :end) option: #{boundary.inspect}" 1839 end 1840 1841 literal_append(sql, offset) 1842 sql << (direction == :preceding ? " PRECEDING" : " FOLLOWING") 1843 end 1844 end