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
309 def add_conversion_proc(oid, callable=nil, &block)
310   conversion_procs[oid] = callable || block
311 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
316 def add_named_conversion_proc(name, &block)
317   unless oid = from(:pg_type).where(:typtype=>['b', 'e'], :typname=>name.to_s).get(:oid)
318     raise Error, "No matching type in pg_type for #{name.inspect}"
319   end
320   add_conversion_proc(oid, block)
321 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
332 def check_constraints(table)
333   m = output_identifier_meth
334 
335   hash = {}
336   _check_constraints_ds.where_each(:conrelid=>regclass_oid(table)) do |row|
337     constraint = m.call(row[:constraint])
338     entry = hash[constraint] ||= {:definition=>row[:definition], :columns=>[]}
339     entry[:columns] << m.call(row[:column]) if row[:column]
340   end
341   
342   hash
343 end
commit_prepared_transaction(transaction_id, opts=OPTS)
[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
323 def commit_prepared_transaction(transaction_id, opts=OPTS)
324   run("COMMIT PREPARED #{literal(transaction_id)}", opts)
325 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
363 def convert_serial_to_identity(table, opts=OPTS)
364   raise Error, "convert_serial_to_identity is only supported on PostgreSQL 10.2+" unless server_version >= 100002
365 
366   server = opts[:server]
367   server_hash = server ? {:server=>server} : OPTS
368   ds = dataset
369   ds = ds.server(server) if server
370 
371   raise Error, "convert_serial_to_identity requires superuser permissions" unless ds.get{current_setting('is_superuser')} == 'on'
372 
373   table_oid = regclass_oid(table)
374   im = input_identifier_meth
375   unless column = (opts[:column] || ((sch = schema(table).find{|_, sc| sc[:primary_key] && sc[:auto_increment]}) && sch[0]))
376     raise Error, "could not determine column to convert from serial to identity automatically"
377   end
378   column = im.call(column)
379 
380   column_num = ds.from(:pg_attribute).
381     where(:attrelid=>table_oid, :attname=>column).
382     get(:attnum)
383 
384   pg_class = Sequel.cast('pg_class', :regclass)
385   res = ds.from(:pg_depend).
386     where(:refclassid=>pg_class, :refobjid=>table_oid, :refobjsubid=>column_num, :classid=>pg_class, :objsubid=>0, :deptype=>%w'a i').
387     select_map([:objid, Sequel.as({:deptype=>'i'}, :v)])
388 
389   case res.length
390   when 0
391     raise Error, "unable to find related sequence when converting serial to identity"
392   when 1
393     seq_oid, already_identity = res.first
394   else
395     raise Error, "more than one linked sequence found when converting serial to identity"
396   end
397 
398   return if already_identity
399 
400   transaction(server_hash) do
401     run("ALTER TABLE #{quote_schema_table(table)} ALTER COLUMN #{quote_identifier(column)} DROP DEFAULT", server_hash)
402 
403     ds.from(:pg_depend).
404       where(:classid=>pg_class, :objid=>seq_oid, :objsubid=>0, :deptype=>'a').
405       update(:deptype=>'i')
406 
407     ds.from(:pg_attribute).
408       where(:attrelid=>table_oid, :attname=>column).
409       update(:attidentity=>'d')
410   end
411 
412   remove_cached_schema(table)
413   nil
414 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
437 def create_function(name, definition, opts=OPTS)
438   self << create_function_sql(name, definition, opts)
439 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
448 def create_language(name, opts=OPTS)
449   self << create_language_sql(name, opts)
450 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
457 def create_schema(name, opts=OPTS)
458   self << create_schema_sql(name, opts)
459 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
462 def create_table(name, options=OPTS, &block)
463   if options[:partition_of]
464     create_partition_of_table_from_generator(name, CreatePartitionOfTableGenerator.new(&block), options)
465     return
466   end
467 
468   super
469 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
472 def create_table?(name, options=OPTS, &block)
473   if options[:partition_of]
474     create_table(name, options.merge!(:if_not_exists=>true), &block)
475     return
476   end
477 
478   super
479 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
493 def create_trigger(table, name, function, opts=OPTS)
494   self << create_trigger_sql(table, name, function, opts)
495 end
database_type()
[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
497 def database_type
498   :postgres
499 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
516 def defer_constraints(opts=OPTS)
517   _set_constraints(' DEFERRED', opts)
518 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
525 def do(code, opts=OPTS)
526   language = opts[:language]
527   run "DO #{"LANGUAGE #{literal(language.to_s)} " if language}#{literal(code)}"
528 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
536 def drop_function(name, opts=OPTS)
537   self << drop_function_sql(name, opts)
538 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
545 def drop_language(name, opts=OPTS)
546   self << drop_language_sql(name, opts)
547 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
554 def drop_schema(name, opts=OPTS)
555   self << drop_schema_sql(name, opts)
556 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
564 def drop_trigger(table, name, opts=OPTS)
565   self << drop_trigger_sql(table, name, opts)
566 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
578 def foreign_key_list(table, opts=OPTS)
579   m = output_identifier_meth
580   schema, _ = opts.fetch(:schema, schema_and_table(table))
581 
582   h = {}
583   fklod_map = FOREIGN_KEY_LIST_ON_DELETE_MAP 
584   reverse = opts[:reverse]
585 
586   (reverse ? _reverse_foreign_key_list_ds : _foreign_key_list_ds).where_each(Sequel[:cl][:oid]=>regclass_oid(table)) do |row|
587     if reverse
588       key = [row[:schema], row[:table], row[:name]]
589     else
590       key = row[:name]
591     end
592 
593     if r = h[key]
594       r[:columns] << m.call(row[:column])
595       r[:key] << m.call(row[:refcolumn])
596     else
597       entry = h[key] = {
598         :name=>m.call(row[:name]),
599         :columns=>[m.call(row[:column])],
600         :key=>[m.call(row[:refcolumn])],
601         :on_update=>fklod_map[row[:on_update]],
602         :on_delete=>fklod_map[row[:on_delete]],
603         :deferrable=>row[:deferrable],
604         :table=>schema ? SQL::QualifiedIdentifier.new(m.call(row[:schema]), m.call(row[:table])) : m.call(row[:table]),
605       }
606 
607       unless schema
608         # If not combining schema information into the :table entry
609         # include it as a separate entry.
610         entry[:schema] = m.call(row[:schema])
611       end
612     end
613   end
614 
615   h.values
616 end
freeze()
[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
618 def freeze
619   server_version
620   supports_prepared_transactions?
621   _schema_ds
622   _select_serial_sequence_ds
623   _select_custom_sequence_ds
624   _select_pk_ds
625   _indexes_ds
626   _check_constraints_ds
627   _foreign_key_list_ds
628   _reverse_foreign_key_list_ds
629   @conversion_procs.freeze
630   super
631 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
647 def immediate_constraints(opts=OPTS)
648   _set_constraints(' IMMEDIATE', opts)
649 end
indexes(table, opts=OPTS)

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

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
652 def indexes(table, opts=OPTS)
653   m = output_identifier_meth
654   cond = {Sequel[:tab][:oid]=>regclass_oid(table, opts)}
655   cond[:indpred] = nil unless opts[:include_partial]
656 
657   indexes = {}
658   _indexes_ds.where_each(cond) do |r|
659     i = indexes[m.call(r[:name])] ||= {:columns=>[], :unique=>r[:unique], :deferrable=>r[:deferrable]}
660     i[:columns] << m.call(r[:column])
661   end
662   indexes
663 end
locks()

Dataset containing all current database locks

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
666 def locks
667   dataset.from(:pg_class).join(:pg_locks, :relation=>:relfilenode).select{[pg_class[:relname], Sequel::SQL::ColumnAll.new(:pg_locks)]}
668 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
676 def notify(channel, opts=OPTS)
677   sql = String.new
678   sql << "NOTIFY "
679   dataset.send(:identifier_append, sql, channel)
680   if payload = opts[:payload]
681     sql << ", "
682     dataset.literal_append(sql, payload.to_s)
683   end
684   execute_ddl(sql, opts)
685 end
primary_key(table, opts=OPTS)

Return primary key for the given table.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
688 def primary_key(table, opts=OPTS)
689   quoted_table = quote_schema_table(table)
690   Sequel.synchronize{return @primary_keys[quoted_table] if @primary_keys.has_key?(quoted_table)}
691   value = _select_pk_ds.where_single_value(Sequel[:pg_class][:oid] => regclass_oid(table, opts))
692   Sequel.synchronize{@primary_keys[quoted_table] = value}
693 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
696 def primary_key_sequence(table, opts=OPTS)
697   quoted_table = quote_schema_table(table)
698   Sequel.synchronize{return @primary_key_sequences[quoted_table] if @primary_key_sequences.has_key?(quoted_table)}
699   cond = {Sequel[:t][:oid] => regclass_oid(table, opts)}
700   value = if pks = _select_serial_sequence_ds.first(cond)
701     literal(SQL::QualifiedIdentifier.new(pks[:schema], pks[:sequence]))
702   elsif pks = _select_custom_sequence_ds.first(cond)
703     literal(SQL::QualifiedIdentifier.new(pks[:schema], LiteralString.new(pks[:sequence])))
704   end
705 
706   Sequel.synchronize{@primary_key_sequences[quoted_table] = value} if value
707 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
715 def refresh_view(name, opts=OPTS)
716   run "REFRESH MATERIALIZED VIEW#{' CONCURRENTLY' if opts[:concurrently]} #{quote_schema_table(name)}"
717 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
721 def reset_primary_key_sequence(table)
722   return unless seq = primary_key_sequence(table)
723   pk = SQL::Identifier.new(primary_key(table))
724   db = self
725   s, t = schema_and_table(table)
726   table = Sequel.qualify(s, t) if s
727 
728   if server_version >= 100000
729     seq_ds = metadata_dataset.from(:pg_sequence).where(:seqrelid=>regclass_oid(LiteralString.new(seq)))
730     increment_by = :seqincrement
731     min_value = :seqmin
732   # :nocov:
733   else
734     seq_ds = metadata_dataset.from(LiteralString.new(seq))
735     increment_by = :increment_by
736     min_value = :min_value
737   # :nocov:
738   end
739 
740   get{setval(seq, db[table].select(coalesce(max(pk)+seq_ds.select(increment_by), seq_ds.select(min_value))), false)}
741 end
rollback_prepared_transaction(transaction_id, opts=OPTS)
[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
743 def rollback_prepared_transaction(transaction_id, opts=OPTS)
744   run("ROLLBACK PREPARED #{literal(transaction_id)}", opts)
745 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
749 def serial_primary_key_options
750   # :nocov:
751   auto_increment_key = server_version >= 100002 ? :identity : :serial
752   # :nocov:
753   {:primary_key => true, auto_increment_key => true, :type=>Integer}
754 end
server_version(server=nil)

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

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
757 def server_version(server=nil)
758   return @server_version if @server_version
759   ds = dataset
760   ds = ds.server(server) if server
761   @server_version = swallow_database_error{ds.with_sql("SELECT CAST(current_setting('server_version_num') AS integer) AS v").single_value} || 0
762 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
765 def supports_create_table_if_not_exists?
766   server_version >= 90100
767 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
770 def supports_deferrable_constraints?
771   server_version >= 90000
772 end
supports_deferrable_foreign_key_constraints?()

PostgreSQL supports deferrable foreign key constraints.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
775 def supports_deferrable_foreign_key_constraints?
776   true
777 end
supports_drop_table_if_exists?()

PostgreSQL supports DROP TABLE IF EXISTS

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
780 def supports_drop_table_if_exists?
781   true
782 end
supports_partial_indexes?()

PostgreSQL supports partial indexes.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
785 def supports_partial_indexes?
786   true
787 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
796 def supports_prepared_transactions?
797   return @supports_prepared_transactions if defined?(@supports_prepared_transactions)
798   @supports_prepared_transactions = self['SHOW max_prepared_transactions'].get.to_i > 0
799 end
supports_savepoints?()

PostgreSQL supports savepoints

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
802 def supports_savepoints?
803   true
804 end
supports_transaction_isolation_levels?()

PostgreSQL supports transaction isolation levels

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
807 def supports_transaction_isolation_levels?
808   true
809 end
supports_transactional_ddl?()

PostgreSQL supports transaction DDL statements.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
812 def supports_transactional_ddl?
813   true
814 end
supports_trigger_conditions?()

PostgreSQL 9.0+ supports trigger conditions.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
790 def supports_trigger_conditions?
791   server_version >= 90000
792 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
825 def tables(opts=OPTS, &block)
826   pg_class_relname(['r', 'p'], opts, &block)
827 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
831 def type_supported?(type)
832   Sequel.synchronize{return @supported_types[type] if @supported_types.has_key?(type)}
833   supported = from(:pg_type).where(:typtype=>'b', :typname=>type.to_s).count > 0
834   Sequel.synchronize{return @supported_types[type] = supported}
835 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
844 def values(v)
845   raise Error, "Cannot provide an empty array for values" if v.empty?
846   @default_dataset.clone(:values=>v)
847 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
857 def views(opts=OPTS)
858   relkind = opts[:materialized] ? 'm' : 'v'
859   pg_class_relname(relkind, opts)
860 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
873 def with_advisory_lock(lock_id, opts=OPTS)
874   ds = dataset
875   if server = opts[:server]
876     ds = ds.server(server)
877   end
878 
879   synchronize(server) do |c|
880     begin
881       if opts[:wait]
882         ds.get{pg_advisory_lock(lock_id)}
883         locked = true
884       else
885         unless locked = ds.get{pg_try_advisory_lock(lock_id)}
886           raise AdvisoryLockError, "unable to acquire advisory lock #{lock_id.inspect}"
887         end
888       end
889 
890       yield
891     ensure
892       ds.get{pg_advisory_unlock(lock_id)} if locked
893     end
894   end
895 end