module Sequel::Postgres::DatabaseMethods

  1. lib/sequel/adapters/shared/postgres.rb

Constants

DATABASE_ERROR_REGEXPS = [ # Add this check first, since otherwise it's possible for users to control # which exception class is generated. [/invalid input syntax/, DatabaseError], [/duplicate key value violates unique constraint/, UniqueConstraintViolation], [/violates foreign key constraint/, ForeignKeyConstraintViolation], [/violates check constraint/, CheckConstraintViolation], [/violates not-null constraint/, NotNullConstraintViolation], [/conflicting key value violates exclusion constraint/, ExclusionConstraintViolation], [/could not serialize access/, SerializationFailure], [/could not obtain lock on row in relation/, DatabaseLockTimeout], ].freeze  
FOREIGN_KEY_LIST_ON_DELETE_MAP = {'a'=>:no_action, 'r'=>:restrict, 'c'=>:cascade, 'n'=>:set_null, 'd'=>:set_default}.freeze  
MAX_DATE = Date.new(5874897, 12, 31)  
MAX_TIMESTAMP = (Time.utc(294277) - Rational(1, 1000000)).freeze  
MIN_DATE = Date.new(-4713, 11, 24)  
MIN_TIMESTAMP = Time.utc(-4713, 11, 24).freeze  
ON_COMMIT = {:drop => 'DROP', :delete_rows => 'DELETE ROWS', :preserve_rows => 'PRESERVE ROWS'}.freeze  
SELECT_CUSTOM_SEQUENCE_SQL = (<<-end_sql SELECT name.nspname AS "schema", CASE WHEN split_part(pg_get_expr(def.adbin, attr.attrelid), '''', 2) ~ '.' THEN substr(split_part(pg_get_expr(def.adbin, attr.attrelid), '''', 2), strpos(split_part(pg_get_expr(def.adbin, attr.attrelid), '''', 2), '.')+1) ELSE split_part(pg_get_expr(def.adbin, attr.attrelid), '''', 2) END AS "sequence" FROM pg_class t JOIN pg_namespace name ON (t.relnamespace = name.oid) JOIN pg_attribute attr ON (t.oid = attrelid) JOIN pg_attrdef def ON (adrelid = attrelid AND adnum = attnum) JOIN pg_constraint cons ON (conrelid = adrelid AND adnum = conkey[1]) WHERE cons.contype = 'p' AND pg_get_expr(def.adbin, attr.attrelid) ~* 'nextval' end_sql ).strip.gsub(/\s+/, ' ').freeze  

SQL fragment for custom sequences (ones not created by serial primary key), Returning the schema and literal form of the sequence name, by parsing the column defaults table.
SELECT_PK_SQL = (<<-end_sql SELECT pg_attribute.attname AS pk FROM pg_class, pg_attribute, pg_index, pg_namespace WHERE pg_class.oid = pg_attribute.attrelid AND pg_class.relnamespace = pg_namespace.oid AND pg_class.oid = pg_index.indrelid AND pg_index.indkey[0] = pg_attribute.attnum AND pg_index.indisprimary = 't' end_sql ).strip.gsub(/\s+/, ' ').freeze  

SQL fragment for determining primary key column for the given table. Only returns the first primary key if the table has a composite primary key.
SELECT_SERIAL_SEQUENCE_SQL = (<<-end_sql SELECT name.nspname AS "schema", seq.relname AS "sequence" FROM pg_class seq, pg_attribute attr, pg_depend dep, pg_namespace name, pg_constraint cons, pg_class t WHERE seq.oid = dep.objid AND seq.relnamespace = name.oid AND seq.relkind = 'S' AND attr.attrelid = dep.refobjid AND attr.attnum = dep.refobjsubid AND attr.attrelid = cons.conrelid AND attr.attnum = cons.conkey[1] AND attr.attrelid = t.oid AND cons.contype = 'p' end_sql ).strip.gsub(/\s+/, ' ').freeze  

SQL fragment for getting sequence associated with table’s primary key, assuming it was a serial primary key column.
TYPTYPE_METHOD_MAP = { 'c' => :schema_composite_type, 'e' => :schema_enum_type, 'r' => :schema_range_type, 'm' => :schema_multirange_type, }  
VALID_CLIENT_MIN_MESSAGES = %w'DEBUG5 DEBUG4 DEBUG3 DEBUG2 DEBUG1 LOG NOTICE WARNING ERROR FATAL PANIC'.freeze.each(&:freeze)  

Attributes

conversion_procs [R]

A hash of conversion procs, keyed by type integer (oid) and having callable values for the conversion proc for that type.

Public Instance methods

add_conversion_proc(oid, callable=nil, &block)

Set a conversion proc for the given oid. The callable can be passed either as a argument or a block.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
327 def add_conversion_proc(oid, callable=nil, &block)
328   conversion_procs[oid] = callable || block
329 end
add_named_conversion_proc(name, &block)

Add a conversion proc for a named type, using the given block. This should be used for types without fixed OIDs, which includes all types that are not included in a default PostgreSQL installation.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
334 def add_named_conversion_proc(name, &block)
335   unless oid = from(:pg_type).where(:typtype=>['b', 'e'], :typname=>name.to_s).get(:oid)
336     raise Error, "No matching type in pg_type for #{name.inspect}"
337   end
338   add_conversion_proc(oid, block)
339 end
check_constraints(table)

A hash of metadata for CHECK constraints on the table. Keys are CHECK constraint name symbols. Values are hashes with the following keys:

:definition

An SQL fragment for the definition of the constraint

:columns

An array of column symbols for the columns referenced in the constraint, can be an empty array if the database cannot deteremine the column symbols.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
350 def check_constraints(table)
351   m = output_identifier_meth
352 
353   hash = {}
354   _check_constraints_ds.where_each(:conrelid=>regclass_oid(table)) do |row|
355     constraint = m.call(row[:constraint])
356     entry = hash[constraint] ||= {:definition=>row[:definition], :columns=>[], :validated=>row[:validated], :enforced=>row[:enforced]}
357     entry[:columns] << m.call(row[:column]) if row[:column]
358   end
359   
360   hash
361 end
commit_prepared_transaction(transaction_id, opts=OPTS)
[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
341 def commit_prepared_transaction(transaction_id, opts=OPTS)
342   run("COMMIT PREPARED #{literal(transaction_id)}", opts)
343 end
convert_serial_to_identity(table, opts=OPTS)

Convert the first primary key column in the table from being a serial column to being an identity column. If the column is already an identity column, assume it was already converted and make no changes.

Only supported on PostgreSQL 10.2+, since on those versions Sequel will use identity columns instead of serial columns for auto incrementing primary keys. Only supported when running as a superuser, since regular users cannot modify system tables, and there is no way to keep an existing sequence when changing an existing column to be an identity column.

This method can raise an exception in at least the following cases where it may otherwise succeed (there may be additional cases not listed here):

  • The serial column was added after table creation using PostgreSQL <7.3

  • A regular index also exists on the column (such an index can probably be dropped as the primary key index should suffice)

Options:

:column

Specify the column to convert instead of using the first primary key column

:server

Run the SQL on the given server

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
381 def convert_serial_to_identity(table, opts=OPTS)
382   raise Error, "convert_serial_to_identity is only supported on PostgreSQL 10.2+" unless server_version >= 100002
383 
384   server = opts[:server]
385   server_hash = server ? {:server=>server} : OPTS
386   ds = dataset
387   ds = ds.server(server) if server
388 
389   raise Error, "convert_serial_to_identity requires superuser permissions" unless ds.get{current_setting('is_superuser')} == 'on'
390 
391   table_oid = regclass_oid(table)
392   im = input_identifier_meth
393   unless column = (opts[:column] || ((sch = schema(table).find{|_, sc| sc[:primary_key] && sc[:auto_increment]}) && sch[0]))
394     raise Error, "could not determine column to convert from serial to identity automatically"
395   end
396   column = im.call(column)
397 
398   column_num = ds.from(:pg_attribute).
399     where(:attrelid=>table_oid, :attname=>column).
400     get(:attnum)
401 
402   pg_class = Sequel.cast('pg_class', :regclass)
403   res = ds.from(:pg_depend).
404     where(:refclassid=>pg_class, :refobjid=>table_oid, :refobjsubid=>column_num, :classid=>pg_class, :objsubid=>0, :deptype=>%w'a i').
405     select_map([:objid, Sequel.as({:deptype=>'i'}, :v)])
406 
407   case res.length
408   when 0
409     raise Error, "unable to find related sequence when converting serial to identity"
410   when 1
411     seq_oid, already_identity = res.first
412   else
413     raise Error, "more than one linked sequence found when converting serial to identity"
414   end
415 
416   return if already_identity
417 
418   transaction(server_hash) do
419     run("ALTER TABLE #{quote_schema_table(table)} ALTER COLUMN #{quote_identifier(column)} DROP DEFAULT", server_hash)
420 
421     ds.from(:pg_depend).
422       where(:classid=>pg_class, :objid=>seq_oid, :objsubid=>0, :deptype=>'a').
423       update(:deptype=>'i')
424 
425     ds.from(:pg_attribute).
426       where(:attrelid=>table_oid, :attname=>column).
427       update(:attidentity=>'d')
428   end
429 
430   remove_cached_schema(table)
431   nil
432 end
create_function(name, definition, opts=OPTS)

Creates the function in the database. Arguments:

name

name of the function to create

definition

string definition of the function, or object file for a dynamically loaded C function.

opts

options hash:

:args

function arguments, can be either a symbol or string specifying a type or an array of 1-3 elements:

1

argument data type

2

argument name

3

argument mode (e.g. in, out, inout)

:behavior

Should be IMMUTABLE, STABLE, or VOLATILE. PostgreSQL assumes VOLATILE by default.

:parallel

The thread safety attribute of the function. Should be SAFE, UNSAFE, RESTRICTED. PostgreSQL assumes UNSAFE by default.

:cost

The estimated cost of the function, used by the query planner.

:language

The language the function uses. SQL is the default.

:link_symbol

For a dynamically loaded see function, the function’s link symbol if different from the definition argument.

:returns

The data type returned by the function. If you are using OUT or INOUT argument modes, this is ignored. Otherwise, if this is not specified, void is used by default to specify the function is not supposed to return a value.

:rows

The estimated number of rows the function will return. Only use if the function returns SETOF something.

:security_definer

Makes the privileges of the function the same as the privileges of the user who defined the function instead of the privileges of the user who runs the function. There are security implications when doing this, see the PostgreSQL documentation.

:set

Configuration variables to set while the function is being run, can be a hash or an array of two pairs. search_path is often used here if :security_definer is used.

:strict

Makes the function return NULL when any argument is NULL.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
455 def create_function(name, definition, opts=OPTS)
456   self << create_function_sql(name, definition, opts)
457 end
create_language(name, opts=OPTS)

Create the procedural language in the database. Arguments:

name

Name of the procedural language (e.g. plpgsql)

opts

options hash:

:handler

The name of a previously registered function used as a call handler for this language.

:replace

Replace the installed language if it already exists (on PostgreSQL 9.0+).

:trusted

Marks the language being created as trusted, allowing unprivileged users to create functions using this language.

:validator

The name of previously registered function used as a validator of functions defined in this language.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
466 def create_language(name, opts=OPTS)
467   self << create_language_sql(name, opts)
468 end
create_schema(name, opts=OPTS)

Create a schema in the database. Arguments:

name

Name of the schema (e.g. admin)

opts

options hash:

:if_not_exists

Don’t raise an error if the schema already exists (PostgreSQL 9.3+)

:owner

The owner to set for the schema (defaults to current user if not specified)

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
475 def create_schema(name, opts=OPTS)
476   self << create_schema_sql(name, opts)
477 end
create_table(name, options=OPTS, &block)

Support partitions of tables using the :partition_of option.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
480 def create_table(name, options=OPTS, &block)
481   if options[:partition_of]
482     create_partition_of_table_from_generator(name, CreatePartitionOfTableGenerator.new(&block), options)
483     return
484   end
485 
486   super
487 end
create_table?(name, options=OPTS, &block)

Support partitions of tables using the :partition_of option.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
490 def create_table?(name, options=OPTS, &block)
491   if options[:partition_of]
492     create_table(name, options.merge!(:if_not_exists=>true), &block)
493     return
494   end
495 
496   super
497 end
create_trigger(table, name, function, opts=OPTS)

Create a trigger in the database. Arguments:

table

the table on which this trigger operates

name

the name of this trigger

function

the function to call for this trigger, which should return type trigger.

opts

options hash:

:after

Calls the trigger after execution instead of before.

:args

An argument or array of arguments to pass to the function.

:each_row

Calls the trigger for each row instead of for each statement.

:events

Can be :insert, :update, :delete, or an array of any of those. Calls the trigger whenever that type of statement is used. By default, the trigger is called for insert, update, or delete.

:replace

Replace the trigger with the same name if it already exists (PostgreSQL 14+).

:when

A filter to use for the trigger

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
511 def create_trigger(table, name, function, opts=OPTS)
512   self << create_trigger_sql(table, name, function, opts)
513 end
database_type()
[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
515 def database_type
516   :postgres
517 end
defer_constraints(opts=OPTS)

For constraints that are deferrable, defer constraints until transaction commit. Options:

:constraints

An identifier of the constraint, or an array of identifiers for constraints, to apply this change to specific constraints.

:server

The server/shard on which to run the query.

Examples:

DB.defer_constraints
# SET CONSTRAINTS ALL DEFERRED

DB.defer_constraints(constraints: [:c1, Sequel[:sc][:c2]])
# SET CONSTRAINTS "c1", "sc"."s2" DEFERRED
[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
534 def defer_constraints(opts=OPTS)
535   _set_constraints(' DEFERRED', opts)
536 end
do(code, opts=OPTS)

Use PostgreSQL’s DO syntax to execute an anonymous code block. The code should be the literal code string to use in the underlying procedural language. Options:

:language

The procedural language the code is written in. The PostgreSQL default is plpgsql. Can be specified as a string or a symbol.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
543 def do(code, opts=OPTS)
544   language = opts[:language]
545   run "DO #{"LANGUAGE #{literal(language.to_s)} " if language}#{literal(code)}"
546 end
drop_function(name, opts=OPTS)

Drops the function from the database. Arguments:

name

name of the function to drop

opts

options hash:

:args

The arguments for the function. See create_function_sql.

:cascade

Drop other objects depending on this function.

:if_exists

Don’t raise an error if the function doesn’t exist.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
554 def drop_function(name, opts=OPTS)
555   self << drop_function_sql(name, opts)
556 end
drop_language(name, opts=OPTS)

Drops a procedural language from the database. Arguments:

name

name of the procedural language to drop

opts

options hash:

:cascade

Drop other objects depending on this function.

:if_exists

Don’t raise an error if the function doesn’t exist.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
563 def drop_language(name, opts=OPTS)
564   self << drop_language_sql(name, opts)
565 end
drop_schema(name, opts=OPTS)

Drops a schema from the database. Arguments:

name

name of the schema to drop

opts

options hash:

:cascade

Drop all objects in this schema.

:if_exists

Don’t raise an error if the schema doesn’t exist.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
572 def drop_schema(name, opts=OPTS)
573   self << drop_schema_sql(name, opts)
574   remove_all_cached_schemas
575 end
drop_trigger(table, name, opts=OPTS)

Drops a trigger from the database. Arguments:

table

table from which to drop the trigger

name

name of the trigger to drop

opts

options hash:

:cascade

Drop other objects depending on this function.

:if_exists

Don’t raise an error if the function doesn’t exist.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
583 def drop_trigger(table, name, opts=OPTS)
584   self << drop_trigger_sql(table, name, opts)
585 end
foreign_key_list(table, opts=OPTS)

Return full foreign key information using the pg system tables, including :name, :on_delete, :on_update, and :deferrable entries in the hashes.

Supports additional options:

:reverse

Instead of returning foreign keys in the current table, return foreign keys in other tables that reference the current table.

:schema

Set to true to have the :table value in the hashes be a qualified identifier. Set to false to use a separate :schema value with the related schema. Defaults to whether the given table argument is a qualified identifier.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
597 def foreign_key_list(table, opts=OPTS)
598   m = output_identifier_meth
599   schema, _ = opts.fetch(:schema, schema_and_table(table))
600 
601   h = {}
602   fklod_map = FOREIGN_KEY_LIST_ON_DELETE_MAP 
603   reverse = opts[:reverse]
604 
605   (reverse ? _reverse_foreign_key_list_ds : _foreign_key_list_ds).where_each(Sequel[:cl][:oid]=>regclass_oid(table)) do |row|
606     if reverse
607       key = [row[:schema], row[:table], row[:name]]
608     else
609       key = row[:name]
610     end
611 
612     if r = h[key]
613       r[:columns] << m.call(row[:column])
614       r[:key] << m.call(row[:refcolumn])
615     else
616       entry = h[key] = {
617         :name=>m.call(row[:name]),
618         :columns=>[m.call(row[:column])],
619         :key=>[m.call(row[:refcolumn])],
620         :on_update=>fklod_map[row[:on_update]],
621         :on_delete=>fklod_map[row[:on_delete]],
622         :deferrable=>row[:deferrable],
623         :validated=>row[:validated],
624         :enforced=>row[:enforced],
625         :table=>schema ? SQL::QualifiedIdentifier.new(m.call(row[:schema]), m.call(row[:table])) : m.call(row[:table]),
626       }
627 
628       unless schema
629         # If not combining schema information into the :table entry
630         # include it as a separate entry.
631         entry[:schema] = m.call(row[:schema])
632       end
633     end
634   end
635 
636   h.values
637 end
freeze()
[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
639 def freeze
640   server_version
641   supports_prepared_transactions?
642   _schema_ds
643   _select_serial_sequence_ds
644   _select_custom_sequence_ds
645   _select_pk_ds
646   _indexes_ds
647   _check_constraints_ds
648   _foreign_key_list_ds
649   _reverse_foreign_key_list_ds
650   @conversion_procs.freeze
651   super
652 end
immediate_constraints(opts=OPTS)

Immediately apply deferrable constraints.

:constraints

An identifier of the constraint, or an array of identifiers for constraints, to apply this change to specific constraints.

:server

The server/shard on which to run the query.

Examples:

DB.immediate_constraints
# SET CONSTRAINTS ALL IMMEDIATE

DB.immediate_constraints(constraints: [:c1, Sequel[:sc][:c2]])
# SET CONSTRAINTS "c1", "sc"."s2" IMMEDIATE
[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
668 def immediate_constraints(opts=OPTS)
669   _set_constraints(' IMMEDIATE', opts)
670 end
indexes(table, opts=OPTS)

Use the pg_* system tables to determine indexes on a table. Options:

:include_partial

Set to true to include partial indexes

:invalid

Set to true or :only to only return invalid indexes. Set to :include to also return both valid and invalid indexes. When not set or other value given, does not return invalid indexes.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
678 def indexes(table, opts=OPTS)
679   m = output_identifier_meth
680   cond = {Sequel[:tab][:oid]=>regclass_oid(table, opts)}
681   cond[:indpred] = nil unless opts[:include_partial]
682 
683   case opts[:invalid]
684   when true, :only
685     cond[:indisvalid] = false
686   when :include
687     # nothing
688   else
689     cond[:indisvalid] = true
690   end
691 
692   indexes = {}
693   _indexes_ds.where_each(cond) do |r|
694     i = indexes[m.call(r[:name])] ||= {:columns=>[], :unique=>r[:unique], :deferrable=>r[:deferrable]}
695     i[:columns] << m.call(r[:column])
696   end
697   indexes
698 end
locks()

Dataset containing all current database locks

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
701 def locks
702   dataset.from(:pg_class).join(:pg_locks, :relation=>:relfilenode).select{[pg_class[:relname], Sequel::SQL::ColumnAll.new(:pg_locks)]}
703 end
notify(channel, opts=OPTS)

Notifies the given channel. See the PostgreSQL NOTIFY documentation. Options:

:payload

The payload string to use for the NOTIFY statement. Only supported in PostgreSQL 9.0+.

:server

The server to which to send the NOTIFY statement, if the sharding support is being used.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
711 def notify(channel, opts=OPTS)
712   sql = String.new
713   sql << "NOTIFY "
714   dataset.send(:identifier_append, sql, channel)
715   if payload = opts[:payload]
716     sql << ", "
717     dataset.literal_append(sql, payload.to_s)
718   end
719   execute_ddl(sql, opts)
720 end
primary_key(table, opts=OPTS)

Return primary key for the given table.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
723 def primary_key(table, opts=OPTS)
724   quoted_table = quote_schema_table(table)
725   Sequel.synchronize{return @primary_keys[quoted_table] if @primary_keys.has_key?(quoted_table)}
726   value = _select_pk_ds.where_single_value(Sequel[:pg_class][:oid] => regclass_oid(table, opts))
727   Sequel.synchronize{@primary_keys[quoted_table] = value}
728 end
primary_key_sequence(table, opts=OPTS)

Return the sequence providing the default for the primary key for the given table.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
731 def primary_key_sequence(table, opts=OPTS)
732   quoted_table = quote_schema_table(table)
733   Sequel.synchronize{return @primary_key_sequences[quoted_table] if @primary_key_sequences.has_key?(quoted_table)}
734   cond = {Sequel[:t][:oid] => regclass_oid(table, opts)}
735   value = if pks = _select_serial_sequence_ds.first(cond)
736     literal(SQL::QualifiedIdentifier.new(pks[:schema], pks[:sequence]))
737   elsif pks = _select_custom_sequence_ds.first(cond)
738     literal(SQL::QualifiedIdentifier.new(pks[:schema], LiteralString.new(pks[:sequence])))
739   end
740 
741   Sequel.synchronize{@primary_key_sequences[quoted_table] = value} if value
742 end
refresh_view(name, opts=OPTS)

Refresh the materialized view with the given name.

DB.refresh_view(:items_view)
# REFRESH MATERIALIZED VIEW items_view
DB.refresh_view(:items_view, concurrently: true)
# REFRESH MATERIALIZED VIEW CONCURRENTLY items_view
[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
758 def refresh_view(name, opts=OPTS)
759   run "REFRESH MATERIALIZED VIEW#{' CONCURRENTLY' if opts[:concurrently]} #{quote_schema_table(name)}"
760 end
rename_schema(name, new_name)

Rename a schema in the database. Arguments:

name

Current name of the schema

opts

New name for the schema

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
747 def rename_schema(name, new_name)
748   self << rename_schema_sql(name, new_name)
749   remove_all_cached_schemas
750 end
reset_primary_key_sequence(table)

Reset the primary key sequence for the given table, basing it on the maximum current value of the table’s primary key.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
764 def reset_primary_key_sequence(table)
765   return unless seq = primary_key_sequence(table)
766   pk = SQL::Identifier.new(primary_key(table))
767   db = self
768   s, t = schema_and_table(table)
769   table = Sequel.qualify(s, t) if s
770 
771   if server_version >= 100000
772     seq_ds = metadata_dataset.from(:pg_sequence).where(:seqrelid=>regclass_oid(LiteralString.new(seq)))
773     increment_by = :seqincrement
774     min_value = :seqmin
775   # :nocov:
776   else
777     seq_ds = metadata_dataset.from(LiteralString.new(seq))
778     increment_by = :increment_by
779     min_value = :min_value
780   # :nocov:
781   end
782 
783   get{setval(seq, db[table].select(coalesce(max(pk)+seq_ds.select(increment_by), seq_ds.select(min_value))), false)}
784 end
rollback_prepared_transaction(transaction_id, opts=OPTS)
[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
786 def rollback_prepared_transaction(transaction_id, opts=OPTS)
787   run("ROLLBACK PREPARED #{literal(transaction_id)}", opts)
788 end
serial_primary_key_options()

PostgreSQL uses SERIAL psuedo-type instead of AUTOINCREMENT for managing incrementing primary keys.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
792 def serial_primary_key_options
793   # :nocov:
794   auto_increment_key = server_version >= 100002 ? :identity : :serial
795   # :nocov:
796   {:primary_key => true, auto_increment_key => true, :type=>Integer}
797 end
server_version(server=nil)

The version of the PostgreSQL server, used for determining capability.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
800 def server_version(server=nil)
801   return @server_version if @server_version
802   ds = dataset
803   ds = ds.server(server) if server
804   @server_version = swallow_database_error{ds.with_sql("SELECT CAST(current_setting('server_version_num') AS integer) AS v").single_value} || 0
805 end
supports_create_table_if_not_exists?()

PostgreSQL supports CREATE TABLE IF NOT EXISTS on 9.1+

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
808 def supports_create_table_if_not_exists?
809   server_version >= 90100
810 end
supports_deferrable_constraints?()

PostgreSQL 9.0+ supports some types of deferrable constraints beyond foreign key constraints.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
813 def supports_deferrable_constraints?
814   server_version >= 90000
815 end
supports_deferrable_foreign_key_constraints?()

PostgreSQL supports deferrable foreign key constraints.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
818 def supports_deferrable_foreign_key_constraints?
819   true
820 end
supports_drop_table_if_exists?()

PostgreSQL supports DROP TABLE IF EXISTS

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
823 def supports_drop_table_if_exists?
824   true
825 end
supports_partial_indexes?()

PostgreSQL supports partial indexes.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
828 def supports_partial_indexes?
829   true
830 end
supports_prepared_transactions?()

PostgreSQL supports prepared transactions (two-phase commit) if max_prepared_transactions is greater than 0.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
839 def supports_prepared_transactions?
840   return @supports_prepared_transactions if defined?(@supports_prepared_transactions)
841   @supports_prepared_transactions = self['SHOW max_prepared_transactions'].get.to_i > 0
842 end
supports_savepoints?()

PostgreSQL supports savepoints

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
845 def supports_savepoints?
846   true
847 end
supports_transaction_isolation_levels?()

PostgreSQL supports transaction isolation levels

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
850 def supports_transaction_isolation_levels?
851   true
852 end
supports_transactional_ddl?()

PostgreSQL supports transaction DDL statements.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
855 def supports_transactional_ddl?
856   true
857 end
supports_trigger_conditions?()

PostgreSQL 9.0+ supports trigger conditions.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
833 def supports_trigger_conditions?
834   server_version >= 90000
835 end
tables(opts=OPTS, &block)

Array of symbols specifying table names in the current database. The dataset used is yielded to the block if one is provided, otherwise, an array of symbols of table names is returned.

Options:

:qualify

Return the tables as Sequel::SQL::QualifiedIdentifier instances, using the schema the table is located in as the qualifier.

:schema

The schema to search

:server

The server to use

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
868 def tables(opts=OPTS, &block)
869   pg_class_relname(['r', 'p'], opts, &block)
870 end
type_supported?(type)

Check whether the given type name string/symbol (e.g. :hstore) is supported by the database.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
874 def type_supported?(type)
875   Sequel.synchronize{return @supported_types[type] if @supported_types.has_key?(type)}
876   supported = from(:pg_type).where(:typtype=>'b', :typname=>type.to_s).count > 0
877   Sequel.synchronize{return @supported_types[type] = supported}
878 end
values(v)

Creates a dataset that uses the VALUES clause:

DB.values([[1, 2], [3, 4]])
# VALUES ((1, 2), (3, 4))

DB.values([[1, 2], [3, 4]]).order(:column2).limit(1, 1)
# VALUES ((1, 2), (3, 4)) ORDER BY column2 LIMIT 1 OFFSET 1
[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
887 def values(v)
888   raise Error, "Cannot provide an empty array for values" if v.empty?
889   @default_dataset.clone(:values=>v)
890 end
views(opts=OPTS)

Array of symbols specifying view names in the current database.

Options:

:materialized

Return materialized views

:qualify

Return the views as Sequel::SQL::QualifiedIdentifier instances, using the schema the view is located in as the qualifier.

:schema

The schema to search

:server

The server to use

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
900 def views(opts=OPTS)
901   relkind = opts[:materialized] ? 'm' : 'v'
902   pg_class_relname(relkind, opts)
903 end
with_advisory_lock(lock_id, opts=OPTS)

Attempt to acquire an exclusive advisory lock with the given lock_id (which should be a 64-bit integer). If successful, yield to the block, then release the advisory lock when the block exits. If unsuccessful, raise a Sequel::AdvisoryLockError.

DB.with_advisory_lock(1347){DB.get(1)}
# SELECT pg_try_advisory_lock(1357) LIMIT 1
# SELECT 1 AS v LIMIT 1
# SELECT pg_advisory_unlock(1357) LIMIT 1

Options:

:wait

Do not raise an error, instead, wait until the advisory lock can be acquired.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
916 def with_advisory_lock(lock_id, opts=OPTS)
917   ds = dataset
918   if server = opts[:server]
919     ds = ds.server(server)
920   end
921 
922   synchronize(server) do |c|
923     begin
924       if opts[:wait]
925         ds.get{pg_advisory_lock(lock_id)}
926         locked = true
927       else
928         unless locked = ds.get{pg_try_advisory_lock(lock_id)}
929           raise AdvisoryLockError, "unable to acquire advisory lock #{lock_id.inspect}"
930         end
931       end
932 
933       yield
934     ensure
935       ds.get{pg_advisory_unlock(lock_id)} if locked
936     end
937   end
938 end