module Sequel::Postgres::DatasetMethods
Instance methods for datasets that connect to a PostgreSQL database.
Constants
- ACCESS_EXCLUSIVE
- ACCESS_SHARE
- APOS
- APOS_RE
- AS
- BACKSLASH
- BLOB_RE
- BOOL_FALSE
- BOOL_TRUE
- COMMA
- COMMA_SEPARATOR
- CRLF
- DOUBLE_APOS
- EMPTY_STRING
- ESCAPE
- EXCLUSIVE
- EXPLAIN
- EXPLAIN_ANALYZE
- FOR_SHARE
- FROM
- LOCK_MODES
- NULL
- PAREN_CLOSE
- PAREN_OPEN
- PG_TIMESTAMP_FORMAT
- QUERY_PLAN
- ROW_EXCLUSIVE
- ROW_SHARE
- SELECT_VALUES
- SHARE
- SHARE_ROW_EXCLUSIVE
- SHARE_UPDATE_EXCLUSIVE
- SPACE
- SQL_WITH_RECURSIVE
- WINDOW
- XOR_OP
Public Instance Methods
Return the results of an EXPLAIN ANALYZE query as a string
# File lib/sequel/adapters/shared/postgres.rb, line 1218 def analyze explain(:analyze=>true) end
Handle converting the ruby xor operator (^) into the PostgreSQL xor operator (#), and use the ILIKE and NOT ILIKE operators.
# File lib/sequel/adapters/shared/postgres.rb, line 1225 def complex_expression_sql_append(sql, op, args) case op when :^ j = XOR_OP c = false args.each do |a| sql << j if c literal_append(sql, a) c ||= true end when :ILIKE, :'NOT ILIKE' sql << PAREN_OPEN literal_append(sql, args.at(0)) sql << SPACE << op.to_s << SPACE literal_append(sql, args.at(1)) sql << ESCAPE literal_append(sql, BACKSLASH) sql << PAREN_CLOSE else super end end
Disables automatic use of INSERT … RETURNING. You can still use returning manually to force the use of RETURNING when inserting.
This is designed for cases where INSERT RETURNING cannot be used, such as when you are using partitioning with trigger functions or conditional rules, or when you are using a PostgreSQL version less than 8.2, or a PostgreSQL derivative that does not support returning.
Note that when this method is used, insert will not return the primary key of the inserted row, you will have to get the primary key of the inserted row before inserting via nextval, or after inserting via currval or lastval (making sure to use the same database connection for currval or lastval).
# File lib/sequel/adapters/shared/postgres.rb, line 1262 def disable_insert_returning clone(:disable_insert_returning=>true) end
Return the results of an EXPLAIN query as a string
# File lib/sequel/adapters/shared/postgres.rb, line 1267 def explain(opts=OPTS) with_sql((opts[:analyze] ? EXPLAIN_ANALYZE : EXPLAIN) + select_sql).map(QUERY_PLAN).join(CRLF) end
Run a full text search on PostgreSQL. By default, searching for the inclusion of any of the terms in any of the cols.
Options:
- :language
-
The language to use for the search (default: 'simple')
- :plain
-
Whether a plain search should be used (default: false). In this case, terms should be a single string, and it will do a search where cols contains all of the words in terms. This ignores search operators in terms.
- :phrase
-
Similar to :plain, but also adding an ILIKE filter to ensure that returned rows also include the exact phrase used.
- :rank
-
Set to true to order by the rank, so that closer matches are returned first.
# File lib/sequel/adapters/shared/postgres.rb, line 1287 def full_text_search(cols, terms, opts = OPTS) lang = Sequel.cast(opts[:language] || 'simple', :regconfig) terms = terms.join(' | ') if terms.is_a?(Array) columns = full_text_string_join(cols) query_func = (opts[:phrase] || opts[:plain]) ? :plainto_tsquery : :to_tsquery vector = Sequel.function(:to_tsvector, lang, columns) query = Sequel.function(query_func, lang, terms) ds = where(Sequel.lit(["(", " @@ ", ")"], vector, query)) if opts[:phrase] ds = ds.grep(cols, "%#{escape_like(terms)}%", :case_insensitive=>true) end if opts[:rank] ds = ds.order{ts_rank_cd(vector, query)} end ds end
Insert given values into the database.
# File lib/sequel/adapters/shared/postgres.rb, line 1309 def insert(*values) if @opts[:returning] # Already know which columns to return, let the standard code handle it super elsif @opts[:sql] || @opts[:disable_insert_returning] # Raw SQL used or RETURNING disabled, just use the default behavior # and return nil since sequence is not known. super nil else # Force the use of RETURNING with the primary key value, # unless it has been disabled. returning(insert_pk).insert(*values){|r| return r.values.first} end end
Insert a record returning the record inserted. Always returns nil without inserting a query if #disable_insert_returning is used.
# File lib/sequel/adapters/shared/postgres.rb, line 1327 def insert_select(*values) return unless supports_insert_select? server?(:default).with_sql_first(insert_select_sql(*values)) end
The SQL to use for an #insert_select, adds a RETURNING clause to the insert unless the RETURNING clause is already present.
# File lib/sequel/adapters/shared/postgres.rb, line 1334 def insert_select_sql(*values) ds = opts[:returning] ? self : returning ds.insert_sql(*values) end
Locks all tables in the dataset's FROM clause (but not in JOINs) with the specified mode (e.g. 'EXCLUSIVE'). If a block is given, starts a new transaction, locks the table, and yields. If a block is not given just locks the tables. Note that PostgreSQL will probably raise an error if you lock the table outside of an existing transaction. Returns nil.
# File lib/sequel/adapters/shared/postgres.rb, line 1344 def lock(mode, opts=OPTS) if block_given? # perform locking inside a transaction and yield to block @db.transaction(opts){lock(mode, opts); yield} else sql = 'LOCK TABLE ' source_list_append(sql, @opts[:from]) mode = mode.to_s.upcase.strip unless LOCK_MODES.include?(mode) raise Error, "Unsupported lock mode: #{mode}" end sql << " IN #{mode} MODE" @db.execute(sql, opts) end nil end
# File lib/sequel/adapters/shared/postgres.rb, line 1360 def supports_cte?(type=:select) if type == :select server_version >= 80400 else server_version >= 90100 end end
PostgreSQL supports using the WITH clause in subqueries if it supports using WITH at all (i.e. on PostgreSQL 8.4+).
# File lib/sequel/adapters/shared/postgres.rb, line 1370 def supports_cte_in_subqueries? supports_cte? end
DISTINCT ON is a PostgreSQL extension
# File lib/sequel/adapters/shared/postgres.rb, line 1375 def supports_distinct_on? true end
True unless insert returning has been disabled for this dataset.
# File lib/sequel/adapters/shared/postgres.rb, line 1380 def supports_insert_select? !@opts[:disable_insert_returning] end
PostgreSQL 9.3rc1+ supports lateral subqueries
# File lib/sequel/adapters/shared/postgres.rb, line 1385 def supports_lateral_subqueries? server_version >= 90300 end
PostgreSQL supports modifying joined datasets
# File lib/sequel/adapters/shared/postgres.rb, line 1390 def supports_modifying_joins? true end
PostgreSQL supports pattern matching via regular expressions
# File lib/sequel/adapters/shared/postgres.rb, line 1400 def supports_regexp? true end
Returning is always supported.
# File lib/sequel/adapters/shared/postgres.rb, line 1395 def supports_returning?(type) true end
PostgreSQL supports timezones in literal timestamps
# File lib/sequel/adapters/shared/postgres.rb, line 1405 def supports_timestamp_timezones? true end
PostgreSQL 8.4+ supports window functions
# File lib/sequel/adapters/shared/postgres.rb, line 1410 def supports_window_functions? server_version >= 80400 end
Truncates the dataset. Returns nil.
Options:
- :cascade
-
whether to use the CASCADE option, useful when truncating tables with foreign keys.
- :only
-
truncate using ONLY, so child tables are unaffected
- :restart
-
use RESTART IDENTITY to restart any related sequences
:only and :restart only work correctly on PostgreSQL 8.4+.
Usage:
DB[:table].truncate # TRUNCATE TABLE "table" # => nil DB[:table].truncate(:cascade => true, :only=>true, :restart=>true) # TRUNCATE TABLE ONLY "table" RESTART IDENTITY CASCADE # => nil
# File lib/sequel/adapters/shared/postgres.rb, line 1429 def truncate(opts = OPTS) if opts.empty? super() else clone(:truncate_opts=>opts).truncate end end
Return a clone of the dataset with an addition named window that can be referenced in window functions.
# File lib/sequel/adapters/shared/postgres.rb, line 1438 def window(name, opts) clone(:window=>(@opts[:window]||[]) + [[name, SQL::Window.new(opts)]]) end
Protected Instance Methods
If returned primary keys are requested, use RETURNING unless already set on the dataset. If RETURNING is already set, use existing returning values. If RETURNING is only set to return a single columns, return an array of just that column. Otherwise, return an array of hashes.
# File lib/sequel/adapters/shared/postgres.rb, line 1448 def _import(columns, values, opts=OPTS) if @opts[:returning] statements = multi_insert_sql(columns, values) @db.transaction(opts.merge(:server=>@opts[:server])) do statements.map{|st| returning_fetch_rows(st)} end.first.map{|v| v.length == 1 ? v.values.first : v} elsif opts[:return] == :primary_key returning(insert_pk)._import(columns, values, opts) else super end end
Private Instance Methods
Format TRUNCATE statement with PostgreSQL specific options.
# File lib/sequel/adapters/shared/postgres.rb, line 1464 def _truncate_sql(table) to = @opts[:truncate_opts] || {} "TRUNCATE TABLE#{' ONLY' if to[:only]} #{table}#{' RESTART IDENTITY' if to[:restart]}#{' CASCADE' if to[:cascade]}" end
Allow truncation of multiple source tables.
# File lib/sequel/adapters/shared/postgres.rb, line 1470 def check_truncation_allowed! raise(InvalidOperation, "Grouped datasets cannot be truncated") if opts[:group] raise(InvalidOperation, "Joined datasets cannot be truncated") if opts[:join] end
PostgreSQL requires parentheses around compound datasets if they use CTEs, and using them in other places doesn't hurt.
# File lib/sequel/adapters/shared/postgres.rb, line 1550 def compound_dataset_sql_append(sql, ds) sql << PAREN_OPEN super sql << PAREN_CLOSE end
Only include the primary table in the main delete clause
# File lib/sequel/adapters/shared/postgres.rb, line 1476 def delete_from_sql(sql) sql << FROM source_list_append(sql, @opts[:from][0..0]) end
Use USING to specify additional tables in a delete query
# File lib/sequel/adapters/shared/postgres.rb, line 1482 def delete_using_sql(sql) join_from_sql(:USING, sql) end
Concatenate the expressions with a space in between
# File lib/sequel/adapters/shared/postgres.rb, line 1600 def full_text_string_join(cols) cols = Array(cols).map{|x| SQL::Function.new(:COALESCE, x, EMPTY_STRING)} cols = cols.zip([SPACE] * cols.length).flatten cols.pop SQL::StringExpression.new(:'||', *cols) end
Return the primary key to use for RETURNING in an INSERT statement
# File lib/sequel/adapters/shared/postgres.rb, line 1487 def insert_pk if (f = opts[:from]) && !f.empty? case t = f.first when Symbol, String, SQL::Identifier, SQL::QualifiedIdentifier if pk = db.primary_key(t) Sequel::SQL::Identifier.new(pk) end end end end
For multiple table support, PostgreSQL requires at least two from tables, with joins allowed.
# File lib/sequel/adapters/shared/postgres.rb, line 1500 def join_from_sql(type, sql) if(from = @opts[:from][1..-1]).empty? raise(Error, 'Need multiple FROM tables if updating/deleting a dataset with JOINs') if @opts[:join] else sql << SPACE << type.to_s << SPACE source_list_append(sql, from) select_join_sql(sql) end end
Use a generic blob quoting method, hopefully overridden in one of the subadapter methods
# File lib/sequel/adapters/shared/postgres.rb, line 1511 def literal_blob_append(sql, v) sql << APOS << v.gsub(BLOB_RE){|b| "\\#{("%o" % b[0..1].unpack("C")[0]).rjust(3, '0')}"} << APOS end
PostgreSQL uses FALSE for false values
# File lib/sequel/adapters/shared/postgres.rb, line 1516 def literal_false BOOL_FALSE end
PostgreSQL quotes NaN and Infinity.
# File lib/sequel/adapters/shared/postgres.rb, line 1521 def literal_float(value) if value.finite? super elsif value.nan? "'NaN'" elsif value.infinite? == 1 "'Infinity'" else "'-Infinity'" end end
Assume that SQL standard quoting is on, per Sequel's defaults
# File lib/sequel/adapters/shared/postgres.rb, line 1534 def literal_string_append(sql, v) sql << APOS << v.gsub(APOS_RE, DOUBLE_APOS) << APOS end
PostgreSQL uses FALSE for false values
# File lib/sequel/adapters/shared/postgres.rb, line 1539 def literal_true BOOL_TRUE end
PostgreSQL supports multiple rows in INSERT.
# File lib/sequel/adapters/shared/postgres.rb, line 1544 def multi_insert_sql_strategy :values end
Support FOR SHARE locking when using the :share lock style.
# File lib/sequel/adapters/shared/postgres.rb, line 1557 def select_lock_sql(sql) @opts[:lock] == :share ? (sql << FOR_SHARE) : super end
Support VALUES clause instead of the SELECT clause to return rows.
# File lib/sequel/adapters/shared/postgres.rb, line 1562 def select_values_sql(sql) sql << SELECT_VALUES expression_list_append(sql, opts[:values]) end
SQL fragment for named window specifications
# File lib/sequel/adapters/shared/postgres.rb, line 1568 def select_window_sql(sql) if ws = @opts[:window] sql << WINDOW c = false co = COMMA as = AS ws.map do |name, window| sql << co if c literal_append(sql, name) sql << as literal_append(sql, window) c ||= true end end end
Use WITH RECURSIVE instead of WITH if any of the CTEs is recursive
# File lib/sequel/adapters/shared/postgres.rb, line 1585 def select_with_sql_base opts[:with].any?{|w| w[:recursive]} ? SQL_WITH_RECURSIVE : super end
The version of the database server
# File lib/sequel/adapters/shared/postgres.rb, line 1590 def server_version db.server_version(@opts[:server]) end
PostgreSQL supports quoted function names.
# File lib/sequel/adapters/shared/postgres.rb, line 1595 def supports_quoted_function_names? true end
Use FROM to specify additional tables in an update query
# File lib/sequel/adapters/shared/postgres.rb, line 1608 def update_from_sql(sql) join_from_sql(:FROM, sql) end
Only include the primary table in the main update clause
# File lib/sequel/adapters/shared/postgres.rb, line 1613 def update_table_sql(sql) sql << SPACE source_list_append(sql, @opts[:from][0..0]) end