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
322 def add_conversion_proc(oid, callable=nil, &block)
323   conversion_procs[oid] = callable || block
324 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
329 def add_named_conversion_proc(name, &block)
330   unless oid = from(:pg_type).where(:typtype=>['b', 'e'], :typname=>name.to_s).get(:oid)
331     raise Error, "No matching type in pg_type for #{name.inspect}"
332   end
333   add_conversion_proc(oid, block)
334 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
345 def check_constraints(table)
346   m = output_identifier_meth
347 
348   hash = {}
349   _check_constraints_ds.where_each(:conrelid=>regclass_oid(table)) do |row|
350     constraint = m.call(row[:constraint])
351     entry = hash[constraint] ||= {:definition=>row[:definition], :columns=>[], :validated=>row[:validated], :enforced=>row[:enforced]}
352     entry[:columns] << m.call(row[:column]) if row[:column]
353   end
354   
355   hash
356 end
commit_prepared_transaction(transaction_id, opts=OPTS)
[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
336 def commit_prepared_transaction(transaction_id, opts=OPTS)
337   run("COMMIT PREPARED #{literal(transaction_id)}", opts)
338 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
376 def convert_serial_to_identity(table, opts=OPTS)
377   raise Error, "convert_serial_to_identity is only supported on PostgreSQL 10.2+" unless server_version >= 100002
378 
379   server = opts[:server]
380   server_hash = server ? {:server=>server} : OPTS
381   ds = dataset
382   ds = ds.server(server) if server
383 
384   raise Error, "convert_serial_to_identity requires superuser permissions" unless ds.get{current_setting('is_superuser')} == 'on'
385 
386   table_oid = regclass_oid(table)
387   im = input_identifier_meth
388   unless column = (opts[:column] || ((sch = schema(table).find{|_, sc| sc[:primary_key] && sc[:auto_increment]}) && sch[0]))
389     raise Error, "could not determine column to convert from serial to identity automatically"
390   end
391   column = im.call(column)
392 
393   column_num = ds.from(:pg_attribute).
394     where(:attrelid=>table_oid, :attname=>column).
395     get(:attnum)
396 
397   pg_class = Sequel.cast('pg_class', :regclass)
398   res = ds.from(:pg_depend).
399     where(:refclassid=>pg_class, :refobjid=>table_oid, :refobjsubid=>column_num, :classid=>pg_class, :objsubid=>0, :deptype=>%w'a i').
400     select_map([:objid, Sequel.as({:deptype=>'i'}, :v)])
401 
402   case res.length
403   when 0
404     raise Error, "unable to find related sequence when converting serial to identity"
405   when 1
406     seq_oid, already_identity = res.first
407   else
408     raise Error, "more than one linked sequence found when converting serial to identity"
409   end
410 
411   return if already_identity
412 
413   transaction(server_hash) do
414     run("ALTER TABLE #{quote_schema_table(table)} ALTER COLUMN #{quote_identifier(column)} DROP DEFAULT", server_hash)
415 
416     ds.from(:pg_depend).
417       where(:classid=>pg_class, :objid=>seq_oid, :objsubid=>0, :deptype=>'a').
418       update(:deptype=>'i')
419 
420     ds.from(:pg_attribute).
421       where(:attrelid=>table_oid, :attname=>column).
422       update(:attidentity=>'d')
423   end
424 
425   remove_cached_schema(table)
426   nil
427 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
450 def create_function(name, definition, opts=OPTS)
451   self << create_function_sql(name, definition, opts)
452 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
461 def create_language(name, opts=OPTS)
462   self << create_language_sql(name, opts)
463 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
470 def create_schema(name, opts=OPTS)
471   self << create_schema_sql(name, opts)
472 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
475 def create_table(name, options=OPTS, &block)
476   if options[:partition_of]
477     create_partition_of_table_from_generator(name, CreatePartitionOfTableGenerator.new(&block), options)
478     return
479   end
480 
481   super
482 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
485 def create_table?(name, options=OPTS, &block)
486   if options[:partition_of]
487     create_table(name, options.merge!(:if_not_exists=>true), &block)
488     return
489   end
490 
491   super
492 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
506 def create_trigger(table, name, function, opts=OPTS)
507   self << create_trigger_sql(table, name, function, opts)
508 end
database_type()
[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
510 def database_type
511   :postgres
512 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
529 def defer_constraints(opts=OPTS)
530   _set_constraints(' DEFERRED', opts)
531 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
538 def do(code, opts=OPTS)
539   language = opts[:language]
540   run "DO #{"LANGUAGE #{literal(language.to_s)} " if language}#{literal(code)}"
541 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
549 def drop_function(name, opts=OPTS)
550   self << drop_function_sql(name, opts)
551 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
558 def drop_language(name, opts=OPTS)
559   self << drop_language_sql(name, opts)
560 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
567 def drop_schema(name, opts=OPTS)
568   self << drop_schema_sql(name, opts)
569 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
577 def drop_trigger(table, name, opts=OPTS)
578   self << drop_trigger_sql(table, name, opts)
579 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
591 def foreign_key_list(table, opts=OPTS)
592   m = output_identifier_meth
593   schema, _ = opts.fetch(:schema, schema_and_table(table))
594 
595   h = {}
596   fklod_map = FOREIGN_KEY_LIST_ON_DELETE_MAP 
597   reverse = opts[:reverse]
598 
599   (reverse ? _reverse_foreign_key_list_ds : _foreign_key_list_ds).where_each(Sequel[:cl][:oid]=>regclass_oid(table)) do |row|
600     if reverse
601       key = [row[:schema], row[:table], row[:name]]
602     else
603       key = row[:name]
604     end
605 
606     if r = h[key]
607       r[:columns] << m.call(row[:column])
608       r[:key] << m.call(row[:refcolumn])
609     else
610       entry = h[key] = {
611         :name=>m.call(row[:name]),
612         :columns=>[m.call(row[:column])],
613         :key=>[m.call(row[:refcolumn])],
614         :on_update=>fklod_map[row[:on_update]],
615         :on_delete=>fklod_map[row[:on_delete]],
616         :deferrable=>row[:deferrable],
617         :validated=>row[:validated],
618         :enforced=>row[:enforced],
619         :table=>schema ? SQL::QualifiedIdentifier.new(m.call(row[:schema]), m.call(row[:table])) : m.call(row[:table]),
620       }
621 
622       unless schema
623         # If not combining schema information into the :table entry
624         # include it as a separate entry.
625         entry[:schema] = m.call(row[:schema])
626       end
627     end
628   end
629 
630   h.values
631 end
freeze()
[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
633 def freeze
634   server_version
635   supports_prepared_transactions?
636   _schema_ds
637   _select_serial_sequence_ds
638   _select_custom_sequence_ds
639   _select_pk_ds
640   _indexes_ds
641   _check_constraints_ds
642   _foreign_key_list_ds
643   _reverse_foreign_key_list_ds
644   @conversion_procs.freeze
645   super
646 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
662 def immediate_constraints(opts=OPTS)
663   _set_constraints(' IMMEDIATE', opts)
664 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
667 def indexes(table, opts=OPTS)
668   m = output_identifier_meth
669   cond = {Sequel[:tab][:oid]=>regclass_oid(table, opts)}
670   cond[:indpred] = nil unless opts[:include_partial]
671 
672   indexes = {}
673   _indexes_ds.where_each(cond) do |r|
674     i = indexes[m.call(r[:name])] ||= {:columns=>[], :unique=>r[:unique], :deferrable=>r[:deferrable]}
675     i[:columns] << m.call(r[:column])
676   end
677   indexes
678 end
locks()

Dataset containing all current database locks

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
681 def locks
682   dataset.from(:pg_class).join(:pg_locks, :relation=>:relfilenode).select{[pg_class[:relname], Sequel::SQL::ColumnAll.new(:pg_locks)]}
683 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
691 def notify(channel, opts=OPTS)
692   sql = String.new
693   sql << "NOTIFY "
694   dataset.send(:identifier_append, sql, channel)
695   if payload = opts[:payload]
696     sql << ", "
697     dataset.literal_append(sql, payload.to_s)
698   end
699   execute_ddl(sql, opts)
700 end
primary_key(table, opts=OPTS)

Return primary key for the given table.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
703 def primary_key(table, opts=OPTS)
704   quoted_table = quote_schema_table(table)
705   Sequel.synchronize{return @primary_keys[quoted_table] if @primary_keys.has_key?(quoted_table)}
706   value = _select_pk_ds.where_single_value(Sequel[:pg_class][:oid] => regclass_oid(table, opts))
707   Sequel.synchronize{@primary_keys[quoted_table] = value}
708 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
711 def primary_key_sequence(table, opts=OPTS)
712   quoted_table = quote_schema_table(table)
713   Sequel.synchronize{return @primary_key_sequences[quoted_table] if @primary_key_sequences.has_key?(quoted_table)}
714   cond = {Sequel[:t][:oid] => regclass_oid(table, opts)}
715   value = if pks = _select_serial_sequence_ds.first(cond)
716     literal(SQL::QualifiedIdentifier.new(pks[:schema], pks[:sequence]))
717   elsif pks = _select_custom_sequence_ds.first(cond)
718     literal(SQL::QualifiedIdentifier.new(pks[:schema], LiteralString.new(pks[:sequence])))
719   end
720 
721   Sequel.synchronize{@primary_key_sequences[quoted_table] = value} if value
722 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
730 def refresh_view(name, opts=OPTS)
731   run "REFRESH MATERIALIZED VIEW#{' CONCURRENTLY' if opts[:concurrently]} #{quote_schema_table(name)}"
732 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
736 def reset_primary_key_sequence(table)
737   return unless seq = primary_key_sequence(table)
738   pk = SQL::Identifier.new(primary_key(table))
739   db = self
740   s, t = schema_and_table(table)
741   table = Sequel.qualify(s, t) if s
742 
743   if server_version >= 100000
744     seq_ds = metadata_dataset.from(:pg_sequence).where(:seqrelid=>regclass_oid(LiteralString.new(seq)))
745     increment_by = :seqincrement
746     min_value = :seqmin
747   # :nocov:
748   else
749     seq_ds = metadata_dataset.from(LiteralString.new(seq))
750     increment_by = :increment_by
751     min_value = :min_value
752   # :nocov:
753   end
754 
755   get{setval(seq, db[table].select(coalesce(max(pk)+seq_ds.select(increment_by), seq_ds.select(min_value))), false)}
756 end
rollback_prepared_transaction(transaction_id, opts=OPTS)
[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
758 def rollback_prepared_transaction(transaction_id, opts=OPTS)
759   run("ROLLBACK PREPARED #{literal(transaction_id)}", opts)
760 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
764 def serial_primary_key_options
765   # :nocov:
766   auto_increment_key = server_version >= 100002 ? :identity : :serial
767   # :nocov:
768   {:primary_key => true, auto_increment_key => true, :type=>Integer}
769 end
server_version(server=nil)

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

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
772 def server_version(server=nil)
773   return @server_version if @server_version
774   ds = dataset
775   ds = ds.server(server) if server
776   @server_version = swallow_database_error{ds.with_sql("SELECT CAST(current_setting('server_version_num') AS integer) AS v").single_value} || 0
777 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
780 def supports_create_table_if_not_exists?
781   server_version >= 90100
782 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
785 def supports_deferrable_constraints?
786   server_version >= 90000
787 end
supports_deferrable_foreign_key_constraints?()

PostgreSQL supports deferrable foreign key constraints.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
790 def supports_deferrable_foreign_key_constraints?
791   true
792 end
supports_drop_table_if_exists?()

PostgreSQL supports DROP TABLE IF EXISTS

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
795 def supports_drop_table_if_exists?
796   true
797 end
supports_partial_indexes?()

PostgreSQL supports partial indexes.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
800 def supports_partial_indexes?
801   true
802 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
811 def supports_prepared_transactions?
812   return @supports_prepared_transactions if defined?(@supports_prepared_transactions)
813   @supports_prepared_transactions = self['SHOW max_prepared_transactions'].get.to_i > 0
814 end
supports_savepoints?()

PostgreSQL supports savepoints

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
817 def supports_savepoints?
818   true
819 end
supports_transaction_isolation_levels?()

PostgreSQL supports transaction isolation levels

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
822 def supports_transaction_isolation_levels?
823   true
824 end
supports_transactional_ddl?()

PostgreSQL supports transaction DDL statements.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
827 def supports_transactional_ddl?
828   true
829 end
supports_trigger_conditions?()

PostgreSQL 9.0+ supports trigger conditions.

[show source] 
    # File lib/sequel/adapters/shared/postgres.rb
805 def supports_trigger_conditions?
806   server_version >= 90000
807 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
840 def tables(opts=OPTS, &block)
841   pg_class_relname(['r', 'p'], opts, &block)
842 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
846 def type_supported?(type)
847   Sequel.synchronize{return @supported_types[type] if @supported_types.has_key?(type)}
848   supported = from(:pg_type).where(:typtype=>'b', :typname=>type.to_s).count > 0
849   Sequel.synchronize{return @supported_types[type] = supported}
850 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
859 def values(v)
860   raise Error, "Cannot provide an empty array for values" if v.empty?
861   @default_dataset.clone(:values=>v)
862 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
872 def views(opts=OPTS)
873   relkind = opts[:materialized] ? 'm' : 'v'
874   pg_class_relname(relkind, opts)
875 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
888 def with_advisory_lock(lock_id, opts=OPTS)
889   ds = dataset
890   if server = opts[:server]
891     ds = ds.server(server)
892   end
893 
894   synchronize(server) do |c|
895     begin
896       if opts[:wait]
897         ds.get{pg_advisory_lock(lock_id)}
898         locked = true
899       else
900         unless locked = ds.get{pg_try_advisory_lock(lock_id)}
901           raise AdvisoryLockError, "unable to acquire advisory lock #{lock_id.inspect}"
902         end
903       end
904 
905       yield
906     ensure
907       ds.get{pg_advisory_unlock(lock_id)} if locked
908     end
909   end
910 end