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
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.
# 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
Public Instance Methods
Save original clone implementation, as some other methods need to call it internally.
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.
# 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 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+.
# 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
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
# 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
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'))
# File lib/sequel/dataset/query.rb 187 def exclude(*cond, &block) 188 add_filter(:where, cond, true, &block) 189 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.
# File lib/sequel/dataset/query.rb 198 def exclude_having(*cond, &block) 199 add_filter(:having, cond, true, &block) 200 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.
# 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
Alias for where.
# File lib/sequel/dataset/query.rb 226 def filter(*cond, &block) 227 where(*cond, &block) 228 end
Returns a cloned dataset with a :update lock style.
DB[:table].for_update # SELECT * FROM table FOR UPDATE
# 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 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)
# 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 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)
# 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
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 '\'))
# 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
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)
# 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 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}, ...]
# 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 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
# 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
Alias of group
# File lib/sequel/dataset/query.rb 372 def group_by(*columns, &block) 373 group(*columns, &block) 374 end
Adds the appropriate CUBE syntax to GROUP BY.
# 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 ROLLUP syntax to GROUP BY.
# 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 GROUPING SETS syntax to GROUP BY.
# 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
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)
# File lib/sequel/dataset/query.rb 434 def having(*cond, &block) 435 add_filter(:having, cond, &block) 436 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
# 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
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.
# 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
Alias of inner_join
# File lib/sequel/dataset/query.rb 487 def join(*args, &block) 488 inner_join(*args, &block) 489 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)))
# 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
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))
# 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
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
# 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
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
# File lib/sequel/dataset/query.rb 690 def lock_style(style) 691 clone(:lock => style) 692 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
# 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 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))
# 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 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
# 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 the source and join condition to use for the MERGE statement.
merge_using(:m2, i1: :i2) # USING m2 ON (i1 = i2)
# File lib/sequel/dataset/query.rb 740 def merge_using(source, join_condition) 741 clone(:merge_using => [source, join_condition].freeze) 742 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}]
# 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 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
# 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 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
# 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
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
# 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
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
# 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 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
# 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
Alias of order
# File lib/sequel/dataset/query.rb 824 def order_by(*columns, &block) 825 order(*columns, &block) 826 end
Alias of order_append.
# File lib/sequel/dataset/query.rb 829 def order_more(*columns, &block) 830 order_append(*columns, &block) 831 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
# 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
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)
# 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
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
# 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
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
# 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
Alias of reverse
# File lib/sequel/dataset/query.rb 914 def reverse_order(*order, &block) 915 reverse(*order, &block) 916 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
# 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 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
# 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 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
# 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
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)
# 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
Alias for select_append.
# File lib/sequel/dataset/query.rb 973 def select_more(*columns, &block) 974 select_append(*columns, &block) 975 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
# 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
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
# File lib/sequel/dataset/query.rb 998 def server(servr) 999 clone(:server=>servr) 1000 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.
# 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
Specify that the check for limits/offsets when updating/deleting be skipped for the dataset.
# 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
Skip locked rows when returning results from this dataset.
# 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
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
# 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 grouping (GROUP or HAVING clause) applied.
DB[:items].group(:a).having(a: 1).where(:b).ungrouped # SELECT * FROM items WHERE b
# 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
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
# File lib/sequel/dataset/query.rb 1064 def union(dataset, opts=OPTS) 1065 compound_clone(:union, dataset, opts) 1066 end
Returns a copy of the dataset with no limit or offset.
DB[:items].limit(10, 20).unlimited # SELECT * FROM items
# 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 order.
DB[:items].order(:a).unordered # SELECT * FROM items
# 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 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.
# File lib/sequel/dataset/query.rb 1126 def where(*cond, &block) 1127 add_filter(:where, cond, &block) 1128 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)
# 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
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
# 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
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.
# 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
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
# 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
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}]
# File lib/sequel/dataset/query.rb 1269 def with_row_proc(callable) 1270 clone(:row_proc=>callable) 1271 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)
# 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
Protected Instance Methods
Add the dataset to the list of compounds
# 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
Return true if the dataset has a non-nil value for any key in opts.
# 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
Whether this dataset is a simple select from an underlying table, such as:
SELECT * FROM table SELECT table.* FROM table
# 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
Private Instance Methods
A frozen array for the currently selected columns.
# 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
An array of SQL::ColumnAll
objects for all FROM and JOIN tables. Used for select_append
and select_prepend.
# 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
Load the extensions into the receiver, without checking if the receiver is frozen.
# 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
If invert is true, invert the condition.
# 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
Append to the current MERGE WHEN clauses. Mutates the hash to add the conditions, if a virtual row block is passed.
# 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
Add the given filter condition. Arguments:
- clause
-
Symbol
or whichSQL
clause to effect, should be :where or :having - cond
-
The filter condition to add
- invert
-
Whether the condition should be inverted (true or false)
- combine
-
How to combine the condition with an existing condition, should be :AND or :OR
# 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
The default :qualify option to use for join tables if one is not specified.
# File lib/sequel/dataset/query.rb 1462 def default_join_table_qualification 1463 :symbol 1464 end
Return self if the dataset already has a server, or a cloned dataset with the default server otherwise.
# File lib/sequel/dataset/query.rb 1537 def default_server 1538 server?(:default) 1539 end
SQL
expression object based on the expr type. See where
.
# 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
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.
# 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
Whether CTEs need to be hoisted from the given ds into the current ds.
# 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
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)]
# 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
Whether the given option key does not affect the generated SQL
.
# File lib/sequel/dataset/query.rb 1542 def non_sql_option?(key) 1543 NON_SQL_OPTIONS.include?(key) 1544 end
Treat the block
as a virtual_row block if not nil
and add the resulting columns to the columns
array (modifies columns
).
# 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
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
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)
# File lib/sequel/dataset/actions.rb 28 def <<(arg) 29 insert(arg) 30 self 31 end
Returns the first record matching the conditions. Examples:
DB[:table][id: 1] # SELECT * FROM table WHERE (id = 1) LIMIT 1 # => {:id=>1}
# 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 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}
# File lib/sequel/dataset/actions.rb 50 def all(&block) 51 _all(block){|a| each{|r| a << r}} 52 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.
# File lib/sequel/dataset/actions.rb 847 def as_hash(key_column, value_column = nil, opts = OPTS) 848 h = opts[:hash] || {} 849 meth = opts[:all] ? :all : :each 850 if value_column 851 return naked.as_hash(key_column, value_column, opts) if row_proc 852 if value_column.is_a?(Array) 853 if key_column.is_a?(Array) 854 public_send(meth){|r| h[r.values_at(*key_column)] = r.values_at(*value_column)} 855 else 856 public_send(meth){|r| h[r[key_column]] = r.values_at(*value_column)} 857 end 858 else 859 if key_column.is_a?(Array) 860 public_send(meth){|r| h[r.values_at(*key_column)] = r[value_column]} 861 else 862 public_send(meth){|r| h[r[key_column]] = r[value_column]} 863 end 864 end 865 elsif key_column.is_a?(Array) 866 public_send(meth){|r| h[key_column.map{|k| r[k]}] = r} 867 else 868 public_send(meth){|r| h[r[key_column]] = r} 869 end 870 h 871 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
# 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 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]
# File lib/sequel/dataset/actions.rb 75 def columns 76 _columns || columns! 77 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]
# 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
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
# 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
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))
# 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
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
.
# 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
Returns true if no records exist in the dataset, false otherwise
DB[:table].empty? # SELECT 1 AS one FROM table LIMIT 1 # => false
# 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 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}]
# File lib/sequel/dataset/actions.rb 216 def first(*args, &block) 217 case args.length 218 when 0 219 unless block 220 return 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
Calls first. If first returns nil (signaling that no row matches), raise a Sequel::NoMatchingRow
exception.
# File lib/sequel/dataset/actions.rb 263 def first!(*args, &block) 264 first(*args, &block) || raise(Sequel::NoMatchingRow.new(self)) 265 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']
# File lib/sequel/dataset/actions.rb 285 def get(column=(no_arg=true; nil), &block) 286 ds = naked 287 if block 288 raise(Error, 'Must call Dataset#get with an argument or a block, not both') unless no_arg 289 ds = ds.select(&block) 290 column = ds.opts[:select] 291 column = nil if column.is_a?(Array) && column.length < 2 292 else 293 case column 294 when Array 295 ds = ds.select(*column) 296 when LiteralString, Symbol, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression 297 if loader = cached_placeholder_literalizer(:_get_loader) do |pl| 298 ds.single_value_ds.select(pl.arg) 299 end 300 301 return loader.get(column) 302 end 303 304 ds = ds.select(column) 305 else 306 if loader = cached_placeholder_literalizer(:_get_alias_loader) do |pl| 307 ds.single_value_ds.select(Sequel.as(pl.arg, :v)) 308 end 309 310 return loader.get(column) 311 end 312 313 ds = ds.select(Sequel.as(column, :v)) 314 end 315 end 316 317 if column.is_a?(Array) 318 if r = ds.single_record 319 r.values_at(*hash_key_symbols(column)) 320 end 321 else 322 ds.single_value 323 end 324 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.
# File lib/sequel/dataset/actions.rb 362 def import(columns, values, opts=OPTS) 363 return insert(columns, values) if values.is_a?(Dataset) 364 365 return if values.empty? 366 raise(Error, 'Using Sequel::Dataset#import with an empty column array is not allowed') if columns.empty? 367 ds = opts[:server] ? server(opts[:server]) : self 368 369 if slice_size = opts.fetch(:commit_every, opts.fetch(:slice, default_import_slice)) 370 offset = 0 371 rows = [] 372 while offset < values.length 373 rows << ds._import(columns, values[offset, slice_size], opts) 374 offset += slice_size 375 end 376 rows.flatten 377 else 378 ds._import(columns, values, opts) 379 end 380 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
# File lib/sequel/dataset/actions.rb 418 def insert(*values, &block) 419 sql = insert_sql(*values) 420 if uses_returning?(:insert) 421 returning_fetch_rows(sql, &block) 422 else 423 execute_insert(sql) 424 end 425 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}]
# File lib/sequel/dataset/actions.rb 437 def last(*args, &block) 438 raise(Error, 'No order specified') unless @opts[:order] 439 reverse.first(*args, &block) 440 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'], ...]
# File lib/sequel/dataset/actions.rb 456 def map(column=nil, &block) 457 if column 458 raise(Error, 'Must call Dataset#map with either an argument or a block, not both') if block 459 return naked.map(column) if row_proc 460 if column.is_a?(Array) 461 super(){|r| r.values_at(*column)} 462 else 463 super(){|r| r[column]} 464 end 465 else 466 super(&block) 467 end 468 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
# File lib/sequel/dataset/actions.rb 477 def max(arg=(no_arg = true), &block) 478 arg = Sequel.virtual_row(&block) if no_arg 479 _aggregate(:max, arg) 480 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
# File lib/sequel/dataset/actions.rb 527 def merge 528 execute_ddl(merge_sql) 529 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
# File lib/sequel/dataset/actions.rb 538 def min(arg=(no_arg = true), &block) 539 arg = Sequel.virtual_row(&block) if no_arg 540 _aggregate(:min, arg) 541 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
.
# File lib/sequel/dataset/actions.rb 555 def multi_insert(hashes, opts=OPTS) 556 return if hashes.empty? 557 columns = hashes.first.keys 558 import(columns, hashes.map{|h| columns.map{|c| h[c]}}, opts) 559 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 # ...
# File lib/sequel/dataset/actions.rb 618 def paged_each(opts=OPTS) 619 unless @opts[:order] 620 raise Sequel::Error, "Dataset#paged_each requires the dataset be ordered" 621 end 622 unless defined?(yield) 623 return enum_for(:paged_each, opts) 624 end 625 626 total_limit = @opts[:limit] 627 offset = @opts[:offset] 628 if server = @opts[:server] 629 opts = Hash[opts] 630 opts[:server] = server 631 end 632 633 rows_per_fetch = opts[:rows_per_fetch] || 1000 634 strategy = if offset || total_limit 635 :offset 636 else 637 opts[:strategy] || :offset 638 end 639 640 db.transaction(opts) do 641 case strategy 642 when :filter 643 filter_values = opts[:filter_values] || proc{|row, exprs| exprs.map{|e| row[hash_key_symbol(e)]}} 644 base_ds = ds = limit(rows_per_fetch) 645 while ds 646 last_row = nil 647 ds.each do |row| 648 last_row = row 649 yield row 650 end 651 ds = (base_ds.where(ignore_values_preceding(last_row, &filter_values)) if last_row) 652 end 653 else 654 offset ||= 0 655 num_rows_yielded = rows_per_fetch 656 total_rows = 0 657 658 while num_rows_yielded == rows_per_fetch && (total_limit.nil? || total_rows < total_limit) 659 if total_limit && total_rows + rows_per_fetch > total_limit 660 rows_per_fetch = total_limit - total_rows 661 end 662 663 num_rows_yielded = 0 664 limit(rows_per_fetch, offset).each do |row| 665 num_rows_yielded += 1 666 total_rows += 1 if total_limit 667 yield row 668 end 669 670 offset += rows_per_fetch 671 end 672 end 673 end 674 675 self 676 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.
# File lib/sequel/dataset/actions.rb 696 def select_hash(key_column, value_column, opts = OPTS) 697 _select_hash(:as_hash, key_column, value_column, opts) 698 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.
# File lib/sequel/dataset/actions.rb 717 def select_hash_groups(key_column, value_column, opts = OPTS) 718 _select_hash(:to_hash_groups, key_column, value_column, opts) 719 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.
# File lib/sequel/dataset/actions.rb 740 def select_map(column=nil, &block) 741 _select_map(column, false, &block) 742 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.
# File lib/sequel/dataset/actions.rb 759 def select_order_map(column=nil, &block) 760 _select_map(column, true, &block) 761 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'}
# File lib/sequel/dataset/actions.rb 769 def single_record 770 _single_record_ds.single_record! 771 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'}
# File lib/sequel/dataset/actions.rb 781 def single_record! 782 with_sql_first(select_sql) 783 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'
# File lib/sequel/dataset/actions.rb 791 def single_value 792 single_value_ds.each do |r| 793 r.each{|_, v| return v} 794 end 795 nil 796 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'
# File lib/sequel/dataset/actions.rb 806 def single_value! 807 with_sql_single_value(select_sql) 808 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
# File lib/sequel/dataset/actions.rb 817 def sum(arg=(no_arg = true), &block) 818 arg = Sequel.virtual_row(&block) if no_arg 819 _aggregate(:sum, arg) 820 end
Alias of as_hash
for backwards compatibility.
# File lib/sequel/dataset/actions.rb 874 def to_hash(*a) 875 as_hash(*a) 876 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.
# File lib/sequel/dataset/actions.rb 902 def to_hash_groups(key_column, value_column = nil, opts = OPTS) 903 h = opts[:hash] || {} 904 meth = opts[:all] ? :all : :each 905 if value_column 906 return naked.to_hash_groups(key_column, value_column, opts) if row_proc 907 if value_column.is_a?(Array) 908 if key_column.is_a?(Array) 909 public_send(meth){|r| (h[r.values_at(*key_column)] ||= []) << r.values_at(*value_column)} 910 else 911 public_send(meth){|r| (h[r[key_column]] ||= []) << r.values_at(*value_column)} 912 end 913 else 914 if key_column.is_a?(Array) 915 public_send(meth){|r| (h[r.values_at(*key_column)] ||= []) << r[value_column]} 916 else 917 public_send(meth){|r| (h[r[key_column]] ||= []) << r[value_column]} 918 end 919 end 920 elsif key_column.is_a?(Array) 921 public_send(meth){|r| (h[key_column.map{|k| r[k]}] ||= []) << r} 922 else 923 public_send(meth){|r| (h[r[key_column]] ||= []) << r} 924 end 925 h 926 end
Truncates the dataset. Returns nil.
DB[:table].truncate # TRUNCATE table # => nil
# File lib/sequel/dataset/actions.rb 932 def truncate 933 execute_ddl(truncate_sql) 934 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))
# File lib/sequel/dataset/actions.rb 958 def update(values=OPTS, &block) 959 sql = update_sql(values) 960 if uses_returning?(:update) 961 returning_fetch_rows(sql, &block) 962 else 963 execute_dui(sql) 964 end 965 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))
# File lib/sequel/dataset/actions.rb 973 def where_all(cond, &block) 974 if loader = _where_loader([cond], nil) 975 loader.all(filter_expr(cond), &block) 976 else 977 where(cond).all(&block) 978 end 979 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))
# File lib/sequel/dataset/actions.rb 987 def where_each(cond, &block) 988 if loader = _where_loader([cond], nil) 989 loader.each(filter_expr(cond), &block) 990 else 991 where(cond).each(&block) 992 end 993 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
# File lib/sequel/dataset/actions.rb 1002 def where_single_value(cond) 1003 if loader = cached_where_placeholder_literalizer([cond], nil, :_where_single_value_loader) do |pl| 1004 single_value_ds.where(pl.arg) 1005 end 1006 1007 loader.get(filter_expr(cond)) 1008 else 1009 where(cond).single_value 1010 end 1011 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.
# File lib/sequel/dataset/actions.rb 1015 def with_sql_all(sql, &block) 1016 _all(block){|a| with_sql_each(sql){|r| a << r}} 1017 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.
# File lib/sequel/dataset/actions.rb 1022 def with_sql_delete(sql) 1023 execute_dui(sql) 1024 end
Run the given SQL
and yield each returned row to the block.
# File lib/sequel/dataset/actions.rb 1028 def with_sql_each(sql) 1029 if rp = row_proc 1030 _with_sql_dataset.fetch_rows(sql){|r| yield rp.call(r)} 1031 else 1032 _with_sql_dataset.fetch_rows(sql){|r| yield r} 1033 end 1034 self 1035 end
Run the given SQL
and return the first row, or nil if no rows were returned. See with_sql_each.
# File lib/sequel/dataset/actions.rb 1039 def with_sql_first(sql) 1040 with_sql_each(sql){|r| return r} 1041 nil 1042 end
Execute the given SQL
and (on most databases) return the primary key of the inserted row.
# File lib/sequel/dataset/actions.rb 1055 def with_sql_insert(sql) 1056 execute_insert(sql) 1057 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.
# File lib/sequel/dataset/actions.rb 1047 def with_sql_single_value(sql) 1048 if r = with_sql_first(sql) 1049 r.each{|_, v| return v} 1050 end 1051 end
Protected Instance Methods
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.
# File lib/sequel/dataset/actions.rb 1065 def _import(columns, values, opts) 1066 trans_opts = Hash[opts] 1067 trans_opts[:server] = @opts[:server] 1068 if opts[:return] == :primary_key 1069 _import_transaction(values, trans_opts){values.map{|v| insert(columns, v)}} 1070 else 1071 stmts = multi_insert_sql(columns, values) 1072 _import_transaction(stmts, trans_opts){stmts.each{|st| execute_dui(st)}} 1073 end 1074 end
Return an array of arrays of values given by the symbols in ret_cols.
# File lib/sequel/dataset/actions.rb 1077 def _select_map_multiple(ret_cols) 1078 map{|r| r.values_at(*ret_cols)} 1079 end
Returns an array of the first value in each row.
# File lib/sequel/dataset/actions.rb 1082 def _select_map_single 1083 k = nil 1084 map{|r| r[k||=r.keys.first]} 1085 end
A dataset for returning single values from the current dataset.
# File lib/sequel/dataset/actions.rb 1088 def single_value_ds 1089 clone(:limit=>1).ungraphed.naked 1090 end
Private Instance Methods
Cached placeholder literalizer for methods that return values using aggregate functions.
# File lib/sequel/dataset/actions.rb 1104 def _aggregate(function, arg) 1105 if loader = cached_placeholder_literalizer(:"_#{function}_loader") do |pl| 1106 aggregate_dataset.limit(1).select(SQL::Function.new(function, pl.arg).as(function)) 1107 end 1108 loader.get(arg) 1109 else 1110 aggregate_dataset.get(SQL::Function.new(function, arg).as(function)) 1111 end 1112 end
Internals of all and with_sql_all
# File lib/sequel/dataset/actions.rb 1095 def _all(block) 1096 a = [] 1097 yield a 1098 post_load(a) 1099 a.each(&block) if block 1100 a 1101 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
# File lib/sequel/dataset/actions.rb 1212 def _hash_key_symbol(s, recursing=false) 1213 case s 1214 when Symbol 1215 _, c, a = split_symbol(s) 1216 (a || c).to_sym 1217 when SQL::Identifier, SQL::Wrapper 1218 _hash_key_symbol(s.value, true) 1219 when SQL::QualifiedIdentifier 1220 _hash_key_symbol(s.column, true) 1221 when SQL::AliasedExpression 1222 _hash_key_symbol(s.alias, true) 1223 when String 1224 s.to_sym if recursing 1225 end 1226 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.
# File lib/sequel/dataset/actions.rb 1117 def _import_transaction(values, trans_opts, &block) 1118 # OK to mutate trans_opts as it is generated by _import 1119 trans_opts[:skip_transaction] = true if values.length <= 1 1120 @db.transaction(trans_opts, &block) 1121 end
Internals of select_hash
and select_hash_groups
# File lib/sequel/dataset/actions.rb 1124 def _select_hash(meth, key_column, value_column, opts=OPTS) 1125 select(*(key_column.is_a?(Array) ? key_column : [key_column]) + (value_column.is_a?(Array) ? value_column : [value_column])). 1126 public_send(meth, hash_key_symbols(key_column), hash_key_symbols(value_column), opts) 1127 end
Internals of select_map
and select_order_map
# File lib/sequel/dataset/actions.rb 1130 def _select_map(column, order, &block) 1131 ds = ungraphed.naked 1132 columns = Array(column) 1133 virtual_row_columns(columns, block) 1134 select_cols = order ? columns.map{|c| c.is_a?(SQL::OrderedExpression) ? c.expression : c} : columns 1135 ds = ds.order(*columns.map{|c| unaliased_identifier(c)}) if order 1136 if column.is_a?(Array) || (columns.length > 1) 1137 ds.select(*select_cols)._select_map_multiple(hash_key_symbols(select_cols)) 1138 else 1139 ds.select(auto_alias_expression(select_cols.first))._select_map_single 1140 end 1141 end
A cached dataset for a single record for this dataset.
# File lib/sequel/dataset/actions.rb 1144 def _single_record_ds 1145 cached_dataset(:_single_record_ds){clone(:limit=>1)} 1146 end
Loader used for where_all
and where_each.
# File lib/sequel/dataset/actions.rb 1149 def _where_loader(where_args, where_block) 1150 cached_where_placeholder_literalizer(where_args, where_block, :_where_loader) do |pl| 1151 where(pl.arg) 1152 end 1153 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.
# File lib/sequel/dataset/actions.rb 1330 def _with_sql_dataset 1331 if @opts[:_with_sql_ds] 1332 self 1333 else 1334 cached_dataset(:_with_sql_ds) do 1335 clone(:_with_sql_ds=>true) 1336 end 1337 end 1338 end
Automatically alias the given expression if it does not have an identifiable alias.
# File lib/sequel/dataset/actions.rb 1156 def auto_alias_expression(v) 1157 case v 1158 when LiteralString, Symbol, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression 1159 v 1160 else 1161 SQL::AliasedExpression.new(v, :v) 1162 end 1163 end
The default number of rows that can be inserted in a single INSERT statement via import. The default is for no limit.
# File lib/sequel/dataset/actions.rb 1167 def default_import_slice 1168 nil 1169 end
Set the server to use to :default unless it is already set in the passed opts
# File lib/sequel/dataset/actions.rb 1172 def default_server_opts(opts) 1173 if @db.sharded? && !opts.has_key?(:server) 1174 opts = Hash[opts] 1175 opts[:server] = @opts[:server] || :default 1176 end 1177 opts 1178 end
Execute the given select SQL
on the database using execute. Use the :read_only server unless a specific server is set.
# File lib/sequel/dataset/actions.rb 1182 def execute(sql, opts=OPTS, &block) 1183 db = @db 1184 if db.sharded? && !opts.has_key?(:server) 1185 opts = Hash[opts] 1186 opts[:server] = @opts[:server] || (@opts[:lock] ? :default : :read_only) 1187 opts 1188 end 1189 db.execute(sql, opts, &block) 1190 end
Execute the given SQL
on the database using execute_ddl.
# File lib/sequel/dataset/actions.rb 1193 def execute_ddl(sql, opts=OPTS, &block) 1194 @db.execute_ddl(sql, default_server_opts(opts), &block) 1195 nil 1196 end
Execute the given SQL
on the database using execute_dui.
# File lib/sequel/dataset/actions.rb 1199 def execute_dui(sql, opts=OPTS, &block) 1200 @db.execute_dui(sql, default_server_opts(opts), &block) 1201 end
Execute the given SQL
on the database using execute_insert.
# File lib/sequel/dataset/actions.rb 1204 def execute_insert(sql, opts=OPTS, &block) 1205 @db.execute_insert(sql, default_server_opts(opts), &block) 1206 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.
# File lib/sequel/dataset/actions.rb 1232 def hash_key_symbol(s) 1233 if v = _hash_key_symbol(s) 1234 v 1235 else 1236 raise(Error, "#{s.inspect} is not supported, should be a Symbol, SQL::Identifier, SQL::QualifiedIdentifier, or SQL::AliasedExpression") 1237 end 1238 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.
# File lib/sequel/dataset/actions.rb 1243 def hash_key_symbols(s) 1244 s.is_a?(Array) ? s.map{|c| hash_key_symbol(c)} : hash_key_symbol(s) 1245 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.
# File lib/sequel/dataset/actions.rb 1250 def ignore_values_preceding(row) 1251 @opts[:order].map{|v| v.is_a?(SQL::OrderedExpression) ? v.expression : v} 1252 1253 order_exprs = @opts[:order].map do |v| 1254 if v.is_a?(SQL::OrderedExpression) 1255 descending = v.descending 1256 v = v.expression 1257 else 1258 descending = false 1259 end 1260 [v, descending] 1261 end 1262 1263 row_values = yield(row, order_exprs.map(&:first)) 1264 1265 last_expr = [] 1266 cond = order_exprs.zip(row_values).map do |(v, descending), value| 1267 expr = last_expr + [SQL::BooleanExpression.new(descending ? :< : :>, v, value)] 1268 last_expr += [SQL::BooleanExpression.new(:'=', v, value)] 1269 Sequel.&(*expr) 1270 end 1271 Sequel.|(*cond) 1272 end
Downcase identifiers by default when outputing them from the database.
# File lib/sequel/dataset/actions.rb 1275 def output_identifier(v) 1276 v = 'untitled' if v == '' 1277 v.to_s.downcase.to_sym 1278 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.
# File lib/sequel/dataset/actions.rb 1284 def post_load(all_records) 1285 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
# File lib/sequel/dataset/actions.rb 1290 def returning_fetch_rows(sql, &block) 1291 if block 1292 default_server.fetch_rows(sql, &block) 1293 nil 1294 else 1295 rows = [] 1296 default_server.fetch_rows(sql){|r| rows << r} 1297 rows 1298 end 1299 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.
# File lib/sequel/dataset/actions.rb 1304 def unaliased_identifier(c) 1305 case c 1306 when Symbol 1307 table, column, aliaz = split_symbol(c) 1308 if aliaz 1309 table ? SQL::QualifiedIdentifier.new(table, column) : Sequel.identifier(column) 1310 else 1311 c 1312 end 1313 when SQL::AliasedExpression 1314 c.expression 1315 when SQL::OrderedExpression 1316 case expr = c.expression 1317 when Symbol, SQL::AliasedExpression 1318 SQL::OrderedExpression.new(unaliased_identifier(expr), c.descending, :nulls=>c.nulls) 1319 else 1320 c 1321 end 1322 else 1323 c 1324 end 1325 end
3 - User Methods relating to SQL Creation
↑ topPublic Instance Methods
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))
# File lib/sequel/dataset/sql.rb 14 def exists 15 SQL::PlaceholderLiteralString.new(EXISTS, [self], true) 16 end
Returns an INSERT SQL
query string. See insert
.
DB[:items].insert_sql(a: 1) # => "INSERT INTO items (a) VALUES (1)"
# 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
Append a literal representation of a value to the given SQL
string.
If an unsupported object is given, an Error
is raised.
# 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
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).
# 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
The SQL
to use for the MERGE statement.
# 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
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.
# 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
Same as select_sql
, not aliased directly to make subclassing simpler.
# File lib/sequel/dataset/sql.rb 176 def sql 177 select_sql 178 end
Returns a TRUNCATE SQL
query string. See truncate
DB[:items].truncate_sql # => 'TRUNCATE items'
# 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
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.
# 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
4 - Methods that describe what the dataset supports
↑ topPublic Instance Methods
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.
# File lib/sequel/dataset/features.rb 19 def provides_accurate_rows_matched? 20 true 21 end
Whether this dataset quotes identifiers.
# File lib/sequel/dataset/features.rb 12 def quote_identifiers? 13 @opts.fetch(:quote_identifiers, true) 14 end
Whether you must use a column alias list for recursive CTEs, false by default.
# File lib/sequel/dataset/features.rb 24 def recursive_cte_requires_column_aliases? 25 false 26 end
Whether type specifiers are required for prepared statement/bound variable argument placeholders (i.e. :bv__integer), false by default.
# File lib/sequel/dataset/features.rb 41 def requires_placeholder_type_specifiers? 42 false 43 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.
# File lib/sequel/dataset/features.rb 33 def requires_sql_standard_datetimes? 34 # SEQUEL6: Remove 35 false 36 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.
# File lib/sequel/dataset/features.rb 48 def supports_cte?(type=:select) 49 false 50 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.
# File lib/sequel/dataset/features.rb 55 def supports_cte_in_subqueries? 56 false 57 end
Whether deleting from joined datasets is supported, false by default.
# File lib/sequel/dataset/features.rb 60 def supports_deleting_joins? 61 supports_modifying_joins? 62 end
Whether the database supports derived column lists (e.g. “table_expr AS table_alias(column_alias1, column_alias2, …)”), true by default.
# File lib/sequel/dataset/features.rb 67 def supports_derived_column_lists? 68 true 69 end
Whether the dataset supports or can emulate the DISTINCT ON clause, false by default.
# File lib/sequel/dataset/features.rb 72 def supports_distinct_on? 73 false 74 end
Whether the dataset supports CUBE with GROUP BY, false by default.
# File lib/sequel/dataset/features.rb 77 def supports_group_cube? 78 false 79 end
Whether the dataset supports ROLLUP with GROUP BY, false by default.
# File lib/sequel/dataset/features.rb 82 def supports_group_rollup? 83 false 84 end
Whether the dataset supports GROUPING SETS with GROUP BY, false by default.
# File lib/sequel/dataset/features.rb 87 def supports_grouping_sets? 88 false 89 end
Whether this dataset supports the insert_select
method for returning all columns values directly from an insert query, false by default.
# File lib/sequel/dataset/features.rb 93 def supports_insert_select? 94 supports_returning?(:insert) 95 end
Whether the dataset supports the INTERSECT and EXCEPT compound operations, true by default.
# File lib/sequel/dataset/features.rb 98 def supports_intersect_except? 99 true 100 end
Whether the dataset supports the INTERSECT ALL and EXCEPT ALL compound operations, true by default.
# File lib/sequel/dataset/features.rb 103 def supports_intersect_except_all? 104 true 105 end
Whether the dataset supports the IS TRUE syntax, true by default.
# File lib/sequel/dataset/features.rb 108 def supports_is_true? 109 true 110 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).
# File lib/sequel/dataset/features.rb 114 def supports_join_using? 115 true 116 end
Whether the dataset supports LATERAL for subqueries in the FROM or JOIN clauses, false by default.
# File lib/sequel/dataset/features.rb 119 def supports_lateral_subqueries? 120 false 121 end
Whether the MERGE statement is supported, false by default.
# File lib/sequel/dataset/features.rb 134 def supports_merge? 135 false 136 end
Whether modifying joined datasets is supported, false by default.
# File lib/sequel/dataset/features.rb 139 def supports_modifying_joins? 140 false 141 end
Whether the IN/NOT IN operators support multiple columns when an array of values is given, true by default.
# File lib/sequel/dataset/features.rb 145 def supports_multiple_column_in? 146 true 147 end
Whether the dataset supports skipping raising an error instead of waiting for locked rows when returning data, false by default.
# File lib/sequel/dataset/features.rb 129 def supports_nowait? 130 false 131 end
Whether the dataset supports or can fully emulate the DISTINCT ON clause, including respecting the ORDER BY clause, false by default.
# File lib/sequel/dataset/features.rb 156 def supports_ordered_distinct_on? 157 supports_distinct_on? 158 end
Whether placeholder literalizers are supported, true by default.
# File lib/sequel/dataset/features.rb 161 def supports_placeholder_literalizer? 162 true 163 end
Whether the dataset supports pattern matching by regular expressions, false by default.
# File lib/sequel/dataset/features.rb 166 def supports_regexp? 167 false 168 end
Whether the dataset supports REPLACE syntax, false by default.
# File lib/sequel/dataset/features.rb 171 def supports_replace? 172 false 173 end
Whether the RETURNING clause is supported for the given type of query, false by default. type
can be :insert, :update, or :delete.
# File lib/sequel/dataset/features.rb 177 def supports_returning?(type) 178 false 179 end
Whether the database supports SELECT *, column FROM table
, true by default.
# File lib/sequel/dataset/features.rb 187 def supports_select_all_and_column? 188 true 189 end
Whether the dataset supports skipping locked rows when returning data, false by default.
# File lib/sequel/dataset/features.rb 182 def supports_skip_locked? 183 false 184 end
Whether the dataset supports timezones in literal timestamps, false by default.
# File lib/sequel/dataset/features.rb 194 def supports_timestamp_timezones? 195 # SEQUEL6: Remove 196 false 197 end
Whether the dataset supports fractional seconds in literal timestamps, true by default.
# File lib/sequel/dataset/features.rb 201 def supports_timestamp_usecs? 202 true 203 end
Whether updating joined datasets is supported, false by default.
# File lib/sequel/dataset/features.rb 206 def supports_updating_joins? 207 supports_modifying_joins? 208 end
Whether the dataset supports WHERE TRUE (or WHERE 1 for databases that that use 1 for true), true by default.
# File lib/sequel/dataset/features.rb 235 def supports_where_true? 236 true 237 end
Whether the dataset supports the WINDOW clause to define windows used by multiple window functions, false by default.
# File lib/sequel/dataset/features.rb 212 def supports_window_clause? 213 false 214 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.
# 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 window functions, false by default.
# File lib/sequel/dataset/features.rb 217 def supports_window_functions? 218 false 219 end
Private Instance Methods
Whether insert(nil) or insert({}) must be emulated by using at least one value.
# File lib/sequel/dataset/features.rb 243 def insert_supports_empty_values? 244 true 245 end
Whether ORDER BY col NULLS FIRST/LAST must be emulated.
# File lib/sequel/dataset/features.rb 253 def requires_emulating_nulls_first? 254 false 255 end
Whether the dataset needs ESCAPE for LIKE for correct behavior.
# File lib/sequel/dataset/features.rb 248 def requires_like_escape? 249 true 250 end
Whether common table expressions are supported in UNION/INTERSECT/EXCEPT clauses.
# File lib/sequel/dataset/features.rb 258 def supports_cte_in_compounds? 259 supports_cte_in_subqueries? 260 end
Whether the dataset supports the FILTER clause for aggregate functions. If not, support is emulated using CASE.
# File lib/sequel/dataset/features.rb 264 def supports_filtered_aggregates? 265 false 266 end
Whether the database supports quoting function names.
# File lib/sequel/dataset/features.rb 269 def supports_quoted_function_names? 270 false 271 end
Whether the RETURNING clause is used for the given dataset. type
can be :insert, :update, or :delete.
# File lib/sequel/dataset/features.rb 275 def uses_returning?(type) 276 opts[:returning] && !@opts[:sql] && supports_returning?(type) 277 end
Whether the dataset uses WITH ROLLUP/CUBE instead of ROLLUP()/CUBE().
# File lib/sequel/dataset/features.rb 280 def uses_with_rollup? 281 false 282 end
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
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.
# File lib/sequel/dataset/misc.rb 25 def initialize(db) 26 @db = db 27 @opts = OPTS 28 @cache = {} 29 freeze 30 end
Public Instance Methods
Define a hash value such that datasets with the same class, DB, and opts will be considered equal.
# File lib/sequel/dataset/misc.rb 34 def ==(o) 35 o.is_a?(self.class) && db == o.db && opts == o.opts 36 end
An object representing the current date or time, should be an instance of Sequel.datetime_class.
# File lib/sequel/dataset/misc.rb 40 def current_datetime 41 Sequel.datetime_class.now 42 end
Return self, as datasets are always frozen.
# File lib/sequel/dataset/misc.rb 50 def dup 51 self 52 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')}
# File lib/sequel/dataset/misc.rb 59 def each_server 60 db.servers.each{|s| yield server(s)} 61 end
Alias for ==
# File lib/sequel/dataset/misc.rb 45 def eql?(o) 46 self == o 47 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\\\%\_'
# File lib/sequel/dataset/misc.rb 68 def escape_like(string) 69 string.gsub(/[\\%_]/){|m| "\\#{m}"} 70 end
Alias of first_source_alias
# File lib/sequel/dataset/misc.rb 91 def first_source 92 first_source_alias 93 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
# 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 original table, not the alias
DB[:table].first_source_table # => :table DB[Sequel[:table].as(:t)].first_source_table # => :table
# 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
Freeze the opts when freezing the dataset.
# File lib/sequel/dataset/misc.rb 74 def freeze 75 @opts.freeze 76 super 77 end
Define a hash value such that datasets with the same class, DB, and opts, will have the same hash value.
# File lib/sequel/dataset/misc.rb 146 def hash 147 [self.class, db, opts].hash 148 end
Returns a string representation of the dataset including the class name and the corresponding SQL
select statement.
# File lib/sequel/dataset/misc.rb 152 def inspect 153 "#<#{visible_class_name}: #{sql.inspect}>" 154 end
Whether this dataset is a joined dataset (multiple FROM tables or any JOINs).
# File lib/sequel/dataset/misc.rb 157 def joined_dataset? 158 !!((opts[:from].is_a?(Array) && opts[:from].size > 1) || opts[:join]) 159 end
The class to use for placeholder literalizers for the current dataset.
# File lib/sequel/dataset/misc.rb 162 def placeholder_literalizer_class 163 ::Sequel::Dataset::PlaceholderLiteralizer 164 end
A placeholder literalizer loader for the current dataset.
# File lib/sequel/dataset/misc.rb 167 def placeholder_literalizer_loader(&block) 168 placeholder_literalizer_class.loader(self, &block) 169 end
The alias to use for the row_number column, used when emulating OFFSET support and for eager limit strategies
# File lib/sequel/dataset/misc.rb 173 def row_number_column 174 :x_sequel_row_number_x 175 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.
# 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
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.
# 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
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
# 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
Return a modified dataset with quote_identifiers set.
# File lib/sequel/dataset/misc.rb 250 def with_quote_identifiers(v) 251 clone(:quote_identifiers=>v, :skip_symbol_cache=>true) 252 end
Protected Instance Methods
The cached columns for the current dataset.
# File lib/sequel/dataset/misc.rb 281 def _columns 282 cache_get(:_columns) 283 end
Retreive a value from the dataset’s cache in a thread safe manner.
# File lib/sequel/dataset/misc.rb 263 def cache_get(k) 264 Sequel.synchronize{@cache[k]} 265 end
Set a value in the dataset’s cache in a thread safe manner.
# File lib/sequel/dataset/misc.rb 268 def cache_set(k, v) 269 Sequel.synchronize{@cache[k] = v} 270 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).
# File lib/sequel/dataset/misc.rb 276 def clear_columns_cache 277 @cache.delete(:_columns) 278 end
Private Instance Methods
Internal recursive version of unqualified_column_for
, handling Strings inside of other objects.
# 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
Check the cache for the given key, returning the value. Otherwise, yield to get the dataset and cache the dataset under the given key.
# 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
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.
# 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 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.
# 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
Set the columns for the current dataset.
# File lib/sequel/dataset/misc.rb 337 def columns=(v) 338 cache_set(:_columns, v) 339 end
Set the db, opts, and cache for the copy of the dataset.
# 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
Return the class name for this dataset, but skip anonymous classes
# 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
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_TYPE_SQL
Mapping of merge types to related
SQL
- N_ARITY_OPERATORS
- QUALIFY_KEYS
- REGEXP_OPERATORS
- TWO_ARITY_OPERATORS
- WILDCARD
Public Class Methods
Given a type (e.g. select) and an array of clauses, return an array of methods to call to build the SQL
string.
# File lib/sequel/dataset/sql.rb 225 def self.clause_methods(type, clauses) 226 clauses.map{|clause| :"#{type}_#{clause}_sql"}.freeze 227 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.
# 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
Public Instance Methods
Append literalization of aliased expression to SQL
string.
# 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 array to SQL
string.
# 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 boolean constant to SQL
string.
# 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 case expression to SQL
string.
# 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 cast expression to SQL
string.
# 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 column all selection to SQL
string.
# 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 complex expression to SQL
string.
# 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 constant to SQL
string.
# File lib/sequel/dataset/sql.rb 468 def constant_sql_append(sql, constant) 469 sql << constant.to_s 470 end
Append literalization of delayed evaluation to SQL
string, causing the delayed evaluation proc to be evaluated.
# 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 function call to SQL
string.
# 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 JOIN clause without ON or USING to SQL
string.
# 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 ON clause to SQL
string.
# 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 USING clause to SQL
string.
# 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 negative boolean constant to SQL
string.
# 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 ordered expression to SQL
string.
# 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 placeholder literal string to SQL
string.
# 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 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
.
# 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 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.
# 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 identifier or unqualified identifier to SQL
string.
# 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 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
).
# File lib/sequel/dataset/sql.rb 715 def quoted_identifier_append(sql, name) 716 sql << '"' << name.to_s.gsub('"', '""') << '"' 717 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).
# 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
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']
# 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
Append literalization of subscripts (SQL
array accesses) to SQL
string.
# 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 windows (for window functions) to SQL
string.
# 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
Protected Instance Methods
Return a from_self
dataset if an order or limit is specified, so it works as expected with UNION, EXCEPT, and INTERSECT clauses.
# 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
Private Instance Methods
Internals of the check_*_allowed! methods
# File lib/sequel/dataset/sql.rb 1058 def _check_modification_allowed!(modifying_joins_supported) 1059 raise(InvalidOperation, "Grouped datasets cannot be modified") if opts[:group] 1060 raise(InvalidOperation, "Joined datasets cannot be modified") if !modifying_joins_supported && joined_dataset? 1061 end
# File lib/sequel/dataset/sql.rb 1268 def _insert_columns_sql(sql, columns) 1269 if columns && !columns.empty? 1270 sql << ' (' 1271 identifier_list_append(sql, columns) 1272 sql << ')' 1273 end 1274 end
# File lib/sequel/dataset/sql.rb 1290 def _insert_values_sql(sql, values) 1291 case values 1292 when Array 1293 if values.empty? 1294 sql << " DEFAULT VALUES" 1295 else 1296 sql << " VALUES " 1297 literal_append(sql, values) 1298 end 1299 when Dataset 1300 sql << ' ' 1301 subselect_sql_append(sql, values) 1302 when LiteralString 1303 sql << ' ' << values 1304 else 1305 raise Error, "Unsupported INSERT values type, should be an Array or Dataset: #{values.inspect}" 1306 end 1307 end
# File lib/sequel/dataset/sql.rb 896 def _merge_delete_sql(sql, data) 897 sql << " THEN DELETE" 898 end
Append the INSERT sql used in a MERGE
# 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
# 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
Append MERGE WHEN conditions, if there are conditions provided.
# File lib/sequel/dataset/sql.rb 922 def _merge_when_conditions_sql(sql, data) 923 if data.has_key?(:conditions) 924 sql << " AND " 925 literal_append(sql, data[:conditions]) 926 end 927 end
Add the WHEN clauses to the MERGE SQL
# File lib/sequel/dataset/sql.rb 911 def _merge_when_sql(sql) 912 raise Error, "no WHEN [NOT] MATCHED clauses provided for MERGE" unless merge_when = @opts[:merge_when] 913 merge_when.each do |data| 914 type = data[:type] 915 sql << MERGE_TYPE_SQL[type] 916 _merge_when_conditions_sql(sql, data) 917 send(:"_merge_#{type}_sql", sql, data) 918 end 919 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.
# File lib/sequel/dataset/sql.rb 933 def _parse_insert_sql_args(values) 934 columns = [] 935 936 case values.size 937 when 0 938 values = [] 939 when 1 940 case vals = values[0] 941 when Hash 942 values = [] 943 vals.each do |k,v| 944 columns << k 945 values << v 946 end 947 when Dataset, Array, LiteralString 948 values = vals 949 end 950 when 2 951 if (v0 = values[0]).is_a?(Array) && ((v1 = values[1]).is_a?(Array) || v1.is_a?(Dataset) || v1.is_a?(LiteralString)) 952 columns, values = v0, v1 953 raise(Error, "Different number of values and columns given to insert_sql") if values.is_a?(Array) and columns.length != values.length 954 end 955 end 956 957 [columns, values] 958 end
Formats the truncate statement. Assumes the table given has already been literalized.
# File lib/sequel/dataset/sql.rb 962 def _truncate_sql(table) 963 "TRUNCATE TABLE #{table}" 964 end
Whether to use from_self
for an aggregate dataset.
# File lib/sequel/dataset/sql.rb 1011 def aggreate_dataset_use_from_self? 1012 options_overlap(COUNT_FROM_SELF_OPTS) 1013 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.
# File lib/sequel/dataset/sql.rb 1006 def aggregate_dataset 1007 (aggreate_dataset_use_from_self? ? from_self : unordered).naked 1008 end
Returns an appropriate symbol for the alias represented by s.
# File lib/sequel/dataset/sql.rb 967 def alias_alias_symbol(s) 968 case s 969 when Symbol 970 s 971 when String 972 s.to_sym 973 when SQL::Identifier 974 s.value.to_s.to_sym 975 else 976 raise Error, "Invalid alias for alias_alias_symbol: #{s.inspect}" 977 end 978 end
Returns an appropriate alias symbol for the given object, which can be a Symbol
, String
, SQL::Identifier
, SQL::QualifiedIdentifier
, or SQL::AliasedExpression
.
# File lib/sequel/dataset/sql.rb 983 def alias_symbol(sym) 984 case sym 985 when Symbol 986 s, t, a = split_symbol(sym) 987 a || s ? (a || t).to_sym : sym 988 when String 989 sym.to_sym 990 when SQL::Identifier 991 sym.value.to_s.to_sym 992 when SQL::QualifiedIdentifier 993 alias_symbol(sym.column) 994 when SQL::AliasedExpression 995 alias_alias_symbol(sym.alias) 996 else 997 raise Error, "Invalid alias for alias_symbol: #{sym.inspect}" 998 end 999 end
Append aliasing expression to SQL
string.
# File lib/sequel/dataset/sql.rb 1016 def as_sql_append(sql, aliaz, column_aliases=nil) 1017 sql << ' AS ' 1018 quote_identifier_append(sql, aliaz) 1019 if column_aliases 1020 raise Error, "#{db.database_type} does not support derived column lists" unless supports_derived_column_lists? 1021 sql << '(' 1022 identifier_list_append(sql, column_aliases) 1023 sql << ')' 1024 end 1025 end
Don’t allow caching SQL
if specifically marked not to.
# File lib/sequel/dataset/sql.rb 1028 def cache_sql? 1029 !@opts[:no_cache_sql] && !cache_get(:_no_cache_sql) 1030 end
Check whether it is allowed to delete from this dataset.
# File lib/sequel/dataset/sql.rb 1048 def check_delete_allowed! 1049 _check_modification_allowed!(supports_deleting_joins?) 1050 end
Check whether it is allowed to insert into this dataset.
# File lib/sequel/dataset/sql.rb 1042 def check_insert_allowed! 1043 _check_modification_allowed!(false) 1044 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.
# File lib/sequel/dataset/sql.rb 1035 def check_modification_allowed! 1036 # SEQUEL6: Remove 1037 Sequel::Deprecation.deprecate("Dataset#check_modification_allowed!", "Use check_{insert,delete,update,truncation}_allowed! instead") 1038 _check_modification_allowed!(supports_modifying_joins?) 1039 end
Raise error if the dataset uses limits or offsets.
# File lib/sequel/dataset/sql.rb 1064 def check_not_limited!(type) 1065 return if @opts[:skip_limit_check] && type != :truncate 1066 raise InvalidOperation, "Dataset##{type} not supported on datasets with limits or offsets" if opts[:limit] || opts[:offset] 1067 end
Check whether it is allowed to update this dataset.
# File lib/sequel/dataset/sql.rb 1053 def check_update_allowed! 1054 _check_modification_allowed!(supports_updating_joins?) 1055 end
Append column list to SQL
string. If the column list is empty, a wildcard (*) is appended.
# File lib/sequel/dataset/sql.rb 1071 def column_list_append(sql, columns) 1072 if (columns.nil? || columns.empty?) 1073 sql << '*' 1074 else 1075 expression_list_append(sql, columns) 1076 end 1077 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.
# File lib/sequel/dataset/sql.rb 1083 def complex_expression_arg_pairs(args) 1084 case args.length 1085 when 1 1086 args[0] 1087 when 2 1088 yield args[0], args[1] 1089 else 1090 args.inject{|m, a| yield(m, a)} 1091 end 1092 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.
# File lib/sequel/dataset/sql.rb 1097 def complex_expression_arg_pairs_append(sql, args, &block) 1098 literal_append(sql, complex_expression_arg_pairs(args, &block)) 1099 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.
# File lib/sequel/dataset/sql.rb 1104 def complex_expression_emulate_append(sql, op, args) 1105 # :nocov: 1106 case op 1107 # :nocov: 1108 when :% 1109 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.function(:MOD, a, b)} 1110 when :>> 1111 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel./(a, Sequel.function(:power, 2, b))} 1112 when :<< 1113 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.*(a, Sequel.function(:power, 2, b))} 1114 when :&, :|, :^ 1115 f = BITWISE_METHOD_MAP[op] 1116 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.function(f, a, b)} 1117 when :'B~' 1118 sql << "((0 - " 1119 literal_append(sql, args[0]) 1120 sql << ") - 1)" 1121 end 1122 end
Append literalization of dataset used in UNION/INTERSECT/EXCEPT clause to SQL
string.
# File lib/sequel/dataset/sql.rb 1125 def compound_dataset_sql_append(sql, ds) 1126 subselect_sql_append(sql, ds) 1127 end
The alias to use for datasets, takes a number to make sure the name is unique.
# File lib/sequel/dataset/sql.rb 1130 def dataset_alias(number) 1131 :"t#{number}" 1132 end
The strftime format to use when literalizing time (Sequel::SQLTime
) values.
# File lib/sequel/dataset/sql.rb 1135 def default_time_format 1136 "'%H:%M:%S.%6N'" 1137 end
The strftime format to use when literalizing timestamp (Time/DateTime) values.
# File lib/sequel/dataset/sql.rb 1140 def default_timestamp_format 1141 "'%Y-%m-%d %H:%M:%S.%6N'" 1142 end
# File lib/sequel/dataset/sql.rb 1144 def delete_delete_sql(sql) 1145 sql << 'DELETE' 1146 end
# File lib/sequel/dataset/sql.rb 1148 def delete_from_sql(sql) 1149 if f = @opts[:from] 1150 sql << ' FROM ' 1151 source_list_append(sql, f) 1152 end 1153 end
Disable caching of SQL
for the current dataset
# File lib/sequel/dataset/sql.rb 1156 def disable_sql_caching! 1157 cache_set(:_no_cache_sql, true) 1158 end
An expression for how to handle an empty array lookup.
# File lib/sequel/dataset/sql.rb 1200 def empty_array_value(op, cols) 1201 {1 => ((op == :IN) ? 0 : 1)} 1202 end
An SQL
FROM clause to use in SELECT statements where the dataset has no from tables.
# File lib/sequel/dataset/sql.rb 1162 def empty_from_sql 1163 nil 1164 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.
# File lib/sequel/dataset/sql.rb 1168 def emulate_function?(name) 1169 false 1170 end
Append literalization of array of expressions to SQL
string, separating them with commas.
# File lib/sequel/dataset/sql.rb 1174 def expression_list_append(sql, columns) 1175 c = false 1176 co = ', ' 1177 columns.each do |col| 1178 sql << co if c 1179 literal_append(sql, col) 1180 c ||= true 1181 end 1182 end
Format the timestamp based on the default_timestamp_format.
# File lib/sequel/dataset/sql.rb 1205 def format_timestamp(v) 1206 db.from_application_timestamp(v).strftime(default_timestamp_format) 1207 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.
# File lib/sequel/dataset/sql.rb 1213 def format_timestamp_usec(usec, ts=timestamp_precision) 1214 # SEQUEL6: Remove 1215 unless ts == 6 1216 usec = usec/(10 ** (6 - ts)) 1217 end 1218 sprintf(".%0#{ts}d", usec) 1219 end
Append literalization of array of grouping elements to SQL
string, seperating them with commas.
# File lib/sequel/dataset/sql.rb 1185 def grouping_element_list_append(sql, columns) 1186 c = false 1187 co = ', ' 1188 columns.each do |col| 1189 sql << co if c 1190 if col.is_a?(Array) && col.empty? 1191 sql << '()' 1192 else 1193 literal_append(sql, Array(col)) 1194 end 1195 c ||= true 1196 end 1197 end
Append literalization of identifier to SQL
string, considering regular strings as SQL
identifiers instead of SQL
strings.
# File lib/sequel/dataset/sql.rb 1224 def identifier_append(sql, v) 1225 if v.is_a?(String) 1226 case v 1227 when LiteralString 1228 sql << v 1229 when SQL::Blob 1230 literal_append(sql, v) 1231 else 1232 quote_identifier_append(sql, v) 1233 end 1234 else 1235 literal_append(sql, v) 1236 end 1237 end
Append literalization of array of identifiers to SQL
string.
# File lib/sequel/dataset/sql.rb 1240 def identifier_list_append(sql, args) 1241 c = false 1242 comma = ', ' 1243 args.each do |a| 1244 sql << comma if c 1245 identifier_append(sql, a) 1246 c ||= true 1247 end 1248 end
Upcase identifiers by default when inputting them into the database.
# File lib/sequel/dataset/sql.rb 1251 def input_identifier(v) 1252 v.to_s.upcase 1253 end
# File lib/sequel/dataset/sql.rb 1264 def insert_columns_sql(sql) 1265 _insert_columns_sql(sql, opts[:columns]) 1266 end
The columns and values to use for an empty insert if the database doesn’t support INSERT with DEFAULT
VALUES.
# File lib/sequel/dataset/sql.rb 1278 def insert_empty_columns_values 1279 [[columns.last], [DEFAULT]] 1280 end
# File lib/sequel/dataset/sql.rb 1282 def insert_insert_sql(sql) 1283 sql << "INSERT" 1284 end
# File lib/sequel/dataset/sql.rb 1255 def insert_into_sql(sql) 1256 sql << " INTO " 1257 if (f = @opts[:from]) && f.length == 1 1258 identifier_append(sql, unaliased_identifier(f.first)) 1259 else 1260 source_list_append(sql, f) 1261 end 1262 end
# File lib/sequel/dataset/sql.rb 1309 def insert_returning_sql(sql) 1310 if opts.has_key?(:returning) 1311 sql << " RETURNING " 1312 column_list_append(sql, Array(opts[:returning])) 1313 end 1314 end
# File lib/sequel/dataset/sql.rb 1286 def insert_values_sql(sql) 1287 _insert_values_sql(sql, opts[:values]) 1288 end
SQL
fragment specifying a JOIN type, converts underscores to spaces and upcases.
# File lib/sequel/dataset/sql.rb 1320 def join_type_sql(join_type) 1321 "#{join_type.to_s.gsub('_', ' ').upcase} JOIN" 1322 end
Append USING clause for JOIN USING
# File lib/sequel/dataset/sql.rb 1325 def join_using_clause_using_sql_append(sql, using_columns) 1326 sql << ' USING (' 1327 column_list_append(sql, using_columns) 1328 sql << ')' 1329 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.
# File lib/sequel/dataset/sql.rb 1333 def literal_array_append(sql, v) 1334 if Sequel.condition_specifier?(v) 1335 literal_expression_append(sql, SQL::BooleanExpression.from_value_pairs(v)) 1336 else 1337 array_sql_append(sql, v) 1338 end 1339 end
SQL
fragment for BigDecimal
# File lib/sequel/dataset/sql.rb 1342 def literal_big_decimal(v) 1343 d = v.to_s("F") 1344 v.nan? || v.infinite? ? "'#{d}'" : d 1345 end
Append literalization of dataset to SQL
string. Does a subselect inside parantheses.
# File lib/sequel/dataset/sql.rb 1353 def literal_dataset_append(sql, v) 1354 sql << 'LATERAL ' if v.opts[:lateral] 1355 sql << '(' 1356 subselect_sql_append(sql, v) 1357 sql << ')' 1358 end
SQL
fragment for Date, using the ISO8601 format.
# File lib/sequel/dataset/sql.rb 1361 def literal_date(v) 1362 v.strftime("'%Y-%m-%d'") 1363 end
Append literalization of date to SQL
string.
# File lib/sequel/dataset/sql.rb 1366 def literal_date_append(sql, v) 1367 sql << literal_date(v) 1368 end
SQL
fragment for DateTime
# File lib/sequel/dataset/sql.rb 1371 def literal_datetime(v) 1372 format_timestamp(v) 1373 end
Append literalization of DateTime to SQL
string.
# File lib/sequel/dataset/sql.rb 1376 def literal_datetime_append(sql, v) 1377 sql << literal_datetime(v) 1378 end
Append literalization of SQL::Expression
to SQL
string.
# File lib/sequel/dataset/sql.rb 1381 def literal_expression_append(sql, v) 1382 v.to_s_append(self, sql) 1383 end
SQL
fragment for false
# File lib/sequel/dataset/sql.rb 1386 def literal_false 1387 "'f'" 1388 end
SQL
fragment for Float
# File lib/sequel/dataset/sql.rb 1391 def literal_float(v) 1392 v.to_s 1393 end
SQL
fragment for Integer
# File lib/sequel/dataset/sql.rb 1401 def literal_integer(v) 1402 v.to_s 1403 end
SQL
fragment for nil
# File lib/sequel/dataset/sql.rb 1406 def literal_nil 1407 "NULL" 1408 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.
# File lib/sequel/dataset/sql.rb 1414 def literal_other_append(sql, v) 1415 # We can't be sure if v will always literalize to the same SQL, so 1416 # don't cache SQL for a dataset that uses this. 1417 disable_sql_caching! 1418 1419 if v.respond_to?(:sql_literal_append) 1420 v.sql_literal_append(self, sql) 1421 elsif v.respond_to?(:sql_literal) 1422 sql << v.sql_literal(self) 1423 else 1424 raise Error, "can't express #{v.inspect} as a SQL literal" 1425 end 1426 end
SQL
fragment for Sequel::SQLTime
, containing just the time part
# File lib/sequel/dataset/sql.rb 1429 def literal_sqltime(v) 1430 v.strftime(default_time_format) 1431 end
Append literalization of Sequel::SQLTime
to SQL
string.
# File lib/sequel/dataset/sql.rb 1434 def literal_sqltime_append(sql, v) 1435 sql << literal_sqltime(v) 1436 end
Append literalization of string to SQL
string.
# File lib/sequel/dataset/sql.rb 1439 def literal_string_append(sql, v) 1440 sql << "'" << v.gsub("'", "''") << "'" 1441 end
Append literalization of symbol to SQL
string.
# File lib/sequel/dataset/sql.rb 1444 def literal_symbol_append(sql, v) 1445 c_table, column, c_alias = split_symbol(v) 1446 if c_table 1447 quote_identifier_append(sql, c_table) 1448 sql << '.' 1449 end 1450 quote_identifier_append(sql, column) 1451 as_sql_append(sql, c_alias) if c_alias 1452 end
SQL
fragment for Time
# File lib/sequel/dataset/sql.rb 1455 def literal_time(v) 1456 format_timestamp(v) 1457 end
Append literalization of Time to SQL
string.
# File lib/sequel/dataset/sql.rb 1460 def literal_time_append(sql, v) 1461 sql << literal_time(v) 1462 end
SQL
fragment for true
# File lib/sequel/dataset/sql.rb 1465 def literal_true 1466 "'t'" 1467 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.
# File lib/sequel/dataset/sql.rb 1473 def multi_insert_sql_strategy 1474 :separate 1475 end
Get the native function name given the emulated function name.
# File lib/sequel/dataset/sql.rb 1479 def native_function_name(emulated_function) 1480 emulated_function 1481 end
Returns a qualified column name (including a table name) if the column name isn’t already qualified.
# File lib/sequel/dataset/sql.rb 1485 def qualified_column_name(column, table) 1486 if column.is_a?(Symbol) 1487 c_table, column, _ = split_symbol(column) 1488 unless c_table 1489 case table 1490 when Symbol 1491 schema, table, t_alias = split_symbol(table) 1492 t_alias ||= Sequel::SQL::QualifiedIdentifier.new(schema, table) if schema 1493 when Sequel::SQL::AliasedExpression 1494 t_alias = table.alias 1495 end 1496 c_table = t_alias || table 1497 end 1498 ::Sequel::SQL::QualifiedIdentifier.new(c_table, column) 1499 else 1500 column 1501 end 1502 end
Qualify the given expression to the given table.
# File lib/sequel/dataset/sql.rb 1505 def qualified_expression(e, table) 1506 Qualifier.new(table).transform(e) 1507 end
# File lib/sequel/dataset/sql.rb 1509 def select_columns_sql(sql) 1510 sql << ' ' 1511 column_list_append(sql, @opts[:select]) 1512 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.
# File lib/sequel/dataset/sql.rb 1528 def select_compounds_sql(sql) 1529 return unless c = @opts[:compounds] 1530 c.each do |type, dataset, all| 1531 sql << ' ' << type.to_s.upcase 1532 sql << ' ALL' if all 1533 sql << ' ' 1534 compound_dataset_sql_append(sql, dataset) 1535 end 1536 end
# File lib/sequel/dataset/sql.rb 1514 def select_distinct_sql(sql) 1515 if distinct = @opts[:distinct] 1516 sql << " DISTINCT" 1517 unless distinct.empty? 1518 sql << " ON (" 1519 expression_list_append(sql, distinct) 1520 sql << ')' 1521 end 1522 end 1523 end
# File lib/sequel/dataset/sql.rb 1538 def select_from_sql(sql) 1539 if f = @opts[:from] 1540 sql << ' FROM ' 1541 source_list_append(sql, f) 1542 elsif f = empty_from_sql 1543 sql << f 1544 end 1545 end
# File lib/sequel/dataset/sql.rb 1547 def select_group_sql(sql) 1548 if group = @opts[:group] 1549 sql << " GROUP BY " 1550 if go = @opts[:group_options] 1551 if go == :"grouping sets" 1552 sql << go.to_s.upcase << '(' 1553 grouping_element_list_append(sql, group) 1554 sql << ')' 1555 elsif uses_with_rollup? 1556 expression_list_append(sql, group) 1557 sql << " WITH " << go.to_s.upcase 1558 else 1559 sql << go.to_s.upcase << '(' 1560 expression_list_append(sql, group) 1561 sql << ')' 1562 end 1563 else 1564 expression_list_append(sql, group) 1565 end 1566 end 1567 end
# File lib/sequel/dataset/sql.rb 1569 def select_having_sql(sql) 1570 if having = @opts[:having] 1571 sql << " HAVING " 1572 literal_append(sql, having) 1573 end 1574 end
# File lib/sequel/dataset/sql.rb 1576 def select_join_sql(sql) 1577 if js = @opts[:join] 1578 js.each{|j| literal_append(sql, j)} 1579 end 1580 end
# File lib/sequel/dataset/sql.rb 1582 def select_limit_sql(sql) 1583 if l = @opts[:limit] 1584 sql << " LIMIT " 1585 literal_append(sql, l) 1586 if o = @opts[:offset] 1587 sql << " OFFSET " 1588 literal_append(sql, o) 1589 end 1590 elsif @opts[:offset] 1591 select_only_offset_sql(sql) 1592 end 1593 end
# File lib/sequel/dataset/sql.rb 1595 def select_lock_sql(sql) 1596 case l = @opts[:lock] 1597 when :update 1598 sql << ' FOR UPDATE' 1599 when String 1600 sql << ' ' << l 1601 end 1602 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.
# File lib/sequel/dataset/sql.rb 1607 def select_only_offset_sql(sql) 1608 sql << " OFFSET " 1609 literal_append(sql, @opts[:offset]) 1610 end
# File lib/sequel/dataset/sql.rb 1612 def select_order_sql(sql) 1613 if o = @opts[:order] 1614 sql << " ORDER BY " 1615 expression_list_append(sql, o) 1616 end 1617 end
# File lib/sequel/dataset/sql.rb 1621 def select_select_sql(sql) 1622 sql << 'SELECT' 1623 end
# File lib/sequel/dataset/sql.rb 1625 def select_where_sql(sql) 1626 if w = @opts[:where] 1627 sql << " WHERE " 1628 literal_append(sql, w) 1629 end 1630 end
# File lib/sequel/dataset/sql.rb 1634 def select_window_sql(sql) 1635 if ws = @opts[:window] 1636 sql << " WINDOW " 1637 c = false 1638 co = ', ' 1639 as = ' AS ' 1640 ws.map do |name, window| 1641 sql << co if c 1642 literal_append(sql, name) 1643 sql << as 1644 literal_append(sql, window) 1645 c ||= true 1646 end 1647 end 1648 end
# File lib/sequel/dataset/sql.rb 1650 def select_with_sql(sql) 1651 return unless supports_cte? 1652 ctes = opts[:with] 1653 return if !ctes || ctes.empty? 1654 sql << select_with_sql_base 1655 c = false 1656 comma = ', ' 1657 ctes.each do |cte| 1658 sql << comma if c 1659 select_with_sql_cte(sql, cte) 1660 c ||= true 1661 end 1662 sql << ' ' 1663 end
# File lib/sequel/dataset/sql.rb 1668 def select_with_sql_base 1669 "WITH " 1670 end
# File lib/sequel/dataset/sql.rb 1672 def select_with_sql_cte(sql, cte) 1673 select_with_sql_prefix(sql, cte) 1674 literal_dataset_append(sql, cte[:dataset]) 1675 end
# File lib/sequel/dataset/sql.rb 1677 def select_with_sql_prefix(sql, w) 1678 quote_identifier_append(sql, w[:name]) 1679 if args = w[:args] 1680 sql << '(' 1681 identifier_list_append(sql, args) 1682 sql << ')' 1683 end 1684 sql << ' AS ' 1685 1686 case w[:materialized] 1687 when true 1688 sql << "MATERIALIZED " 1689 when false 1690 sql << "NOT MATERIALIZED " 1691 end 1692 end
Whether the symbol cache should be skipped when literalizing the dataset
# File lib/sequel/dataset/sql.rb 1695 def skip_symbol_cache? 1696 @opts[:skip_symbol_cache] 1697 end
Append literalization of array of sources/tables to SQL
string, raising an Error
if there are no sources.
# File lib/sequel/dataset/sql.rb 1701 def source_list_append(sql, sources) 1702 raise(Error, 'No source specified for query') if sources.nil? || sources == [] 1703 identifier_list_append(sql, sources) 1704 end
Delegate to Sequel.split_symbol.
# File lib/sequel/dataset/sql.rb 1707 def split_symbol(sym) 1708 Sequel.split_symbol(sym) 1709 end
The string that is appended to to create the SQL
query, the empty string by default.
# File lib/sequel/dataset/sql.rb 1713 def sql_string_origin 1714 String.new 1715 end
The precision to use for SQLTime
instances (time column values without dates). Defaults to timestamp_precision.
# File lib/sequel/dataset/sql.rb 1719 def sqltime_precision 1720 timestamp_precision 1721 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.
# File lib/sequel/dataset/sql.rb 1727 def static_sql(sql) 1728 if append_sql = @opts[:append_sql] 1729 if sql.is_a?(String) 1730 append_sql << sql 1731 else 1732 literal_append(append_sql, sql) 1733 end 1734 else 1735 if sql.is_a?(String) 1736 sql 1737 else 1738 literal(sql) 1739 end 1740 end 1741 end
Append literalization of the subselect to SQL
string.
# File lib/sequel/dataset/sql.rb 1744 def subselect_sql_append(sql, ds) 1745 sds = subselect_sql_dataset(sql, ds) 1746 subselect_sql_append_sql(sql, sds) 1747 unless sds.send(:cache_sql?) 1748 # If subquery dataset does not allow caching SQL, 1749 # then this dataset should not allow caching SQL. 1750 disable_sql_caching! 1751 end 1752 end
# File lib/sequel/dataset/sql.rb 1758 def subselect_sql_append_sql(sql, ds) 1759 ds.sql 1760 end
# File lib/sequel/dataset/sql.rb 1754 def subselect_sql_dataset(sql, ds) 1755 ds.clone(:append_sql=>sql) 1756 end
The number of decimal digits of precision to use in timestamps.
# File lib/sequel/dataset/sql.rb 1763 def timestamp_precision 1764 supports_timestamp_usecs? ? 6 : 0 1765 end
# File lib/sequel/dataset/sql.rb 1773 def update_set_sql(sql) 1774 sql << ' SET ' 1775 values = @opts[:values] 1776 if values.is_a?(Hash) 1777 update_sql_values_hash(sql, values) 1778 else 1779 sql << values 1780 end 1781 end
# File lib/sequel/dataset/sql.rb 1783 def update_sql_values_hash(sql, values) 1784 c = false 1785 eq = ' = ' 1786 values.each do |k, v| 1787 sql << ', ' if c 1788 if k.is_a?(String) && !k.is_a?(LiteralString) 1789 quote_identifier_append(sql, k) 1790 else 1791 literal_append(sql, k) 1792 end 1793 sql << eq 1794 literal_append(sql, v) 1795 c ||= true 1796 end 1797 end
# File lib/sequel/dataset/sql.rb 1767 def update_table_sql(sql) 1768 sql << ' ' 1769 source_list_append(sql, @opts[:from]) 1770 select_join_sql(sql) if supports_modifying_joins? 1771 end
# File lib/sequel/dataset/sql.rb 1799 def update_update_sql(sql) 1800 sql << 'UPDATE' 1801 end
# File lib/sequel/dataset/sql.rb 1803 def window_frame_boundary_sql_append(sql, boundary, direction) 1804 case boundary 1805 when :current 1806 sql << "CURRENT ROW" 1807 when :preceding 1808 sql << "UNBOUNDED PRECEDING" 1809 when :following 1810 sql << "UNBOUNDED FOLLOWING" 1811 else 1812 if boundary.is_a?(Array) 1813 offset, direction = boundary 1814 unless boundary.length == 2 && (direction == :preceding || direction == :following) 1815 raise Error, "invalid window :frame boundary (:start or :end) option: #{boundary.inspect}" 1816 end 1817 else 1818 offset = boundary 1819 end 1820 1821 case offset 1822 when Numeric, String, SQL::Cast 1823 # nothing 1824 else 1825 raise Error, "invalid window :frame boundary (:start or :end) option: #{boundary.inspect}" 1826 end 1827 1828 literal_append(sql, offset) 1829 sql << (direction == :preceding ? " PRECEDING" : " FOLLOWING") 1830 end 1831 end