Module: Sequel::Postgres::DatabaseMethods

Constants

EXCLUDE_SCHEMAS	=	/pg_*\|information_schema/i
PREPARED_ARG_PLACEHOLDER	=	LiteralString.new('$').freeze
RE_CURRVAL_ERROR	=	/currval of sequence "(.)" is not yet defined in this session\|relation "(.)" does not exist/.freeze
SYSTEM_TABLE_REGEXP	=	/^pg\|sql/.freeze
FOREIGN_KEY_LIST_ON_DELETE_MAP	=	{'a'.freeze=>:no_action, 'r'.freeze=>:restrict, 'c'.freeze=>:cascade, 'n'.freeze=>:set_null, 'd'.freeze=>:set_default}.freeze
POSTGRES_DEFAULT_RE	=	/\A(?:B?('.*')::[^']+\|$(-?\d+(?:\.\d+)?)$)\z/
UNLOGGED	=	'UNLOGGED '.freeze
SELECT_CUSTOM_SEQUENCE_SQL	=	(<<-end_sql SELECT name.nspname AS "schema", CASE WHEN split_part(def.adsrc, '''', 2) ~ '.' THEN substr(split_part(def.adsrc, '''', 2), strpos(split_part(def.adsrc, '''', 2), '.')+1) ELSE split_part(def.adsrc, '''', 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 def.adsrc ~* 'nextval' end_sql	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	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	SQL fragment for getting sequence associated with table‘s primary key, assuming it was a serial primary key column.
VALID_CLIENT_MIN_MESSAGES	=	%w'DEBUG5 DEBUG4 DEBUG3 DEBUG2 DEBUG1 LOG NOTICE WARNING ERROR FATAL PANIC'.freeze
EXCLUSION_CONSTRAINT_SQL_STATE	=	'23P01'.freeze
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], ].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

commit_prepared_transaction(transaction_id)

Commit an existing prepared transaction with the given transaction identifier string.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 161
161:       def commit_prepared_transaction(transaction_id)
162:         run("COMMIT PREPARED #{literal(transaction_id)}")
163:       end

create_function(name, definition, 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:
  - element 1 : argument data type
  - element 2 : argument name
  - element 3 : argument mode (e.g. in, out, inout)
- :behavior : Should be IMMUTABLE, STABLE, or VOLATILE. PostgreSQL assumes VOLATILE 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.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 185
185:       def create_function(name, definition, opts={})
186:         self << create_function_sql(name, definition, opts)
187:       end

create_language(name, 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.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 196
196:       def create_language(name, opts={})
197:         self << create_language_sql(name, opts)
198:       end

create_schema(name)

Create a schema in the database. Arguments:

name : Name of the schema (e.g. admin)

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 202
202:       def create_schema(name)
203:         self << create_schema_sql(name)
204:       end

create_trigger(table, name, function, 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.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 216
216:       def create_trigger(table, name, function, opts={})
217:         self << create_trigger_sql(table, name, function, opts)
218:       end

database_type()

PostgreSQL uses the :postgres database type.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 221
221:       def database_type
222:         :postgres
223:       end

do(code, 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.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 230
230:       def do(code, opts={})
231:         language = opts[:language]
232:         run "DO #{"LANGUAGE #{literal(language.to_s)} " if language}#{literal(code)}"
233:       end

drop_function(name, 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.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 241
241:       def drop_function(name, opts={})
242:         self << drop_function_sql(name, opts)
243:       end

drop_language(name, 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.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 250
250:       def drop_language(name, opts={})
251:         self << drop_language_sql(name, opts)
252:       end

drop_schema(name, 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.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 259
259:       def drop_schema(name, opts={})
260:         self << drop_schema_sql(name, opts)
261:       end

drop_trigger(table, name, 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.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 269
269:       def drop_trigger(table, name, opts={})
270:         self << drop_trigger_sql(table, name, opts)
271:       end

foreign_key_list(table, opts={})

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

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 275
275:       def foreign_key_list(table, opts={})
276:         m = output_identifier_meth
277:         schema, _ = opts.fetch(:schema, schema_and_table(table))
278:         range = 0...32
279: 
280:         base_ds = metadata_dataset.
281:           from(:pg_constraint___co).
282:           join(:pg_class___cl, :oid=>:conrelid).
283:           where(:cl__relkind=>'r', :co__contype=>'f', :cl__oid=>regclass_oid(table))
284: 
285:         # We split the parsing into two separate queries, which are merged manually later.
286:         # This is because PostgreSQL stores both the referencing and referenced columns in
287:         # arrays, and I don't know a simple way to not create a cross product, as PostgreSQL
288:         # doesn't appear to have a function that takes an array and element and gives you
289:         # the index of that element in the array.
290: 
291:         ds = base_ds.
292:           join(:pg_attribute___att, :attrelid=>:oid, :attnum=>SQL::Function.new(:ANY, :co__conkey)).
293:           order(:co__conname, SQL::CaseExpression.new(range.map{|x| [SQL::Subscript.new(:co__conkey, [x]), x]}, 32, :att__attnum)).
294:           select(:co__conname___name, :att__attname___column, :co__confupdtype___on_update, :co__confdeltype___on_delete,
295:                  SQL::BooleanExpression.new(:AND, :co__condeferrable, :co__condeferred).as(:deferrable))
296: 
297:         ref_ds = base_ds.
298:           join(:pg_class___cl2, :oid=>:co__confrelid).
299:           join(:pg_attribute___att2, :attrelid=>:oid, :attnum=>SQL::Function.new(:ANY, :co__confkey)).
300:           order(:co__conname, SQL::CaseExpression.new(range.map{|x| [SQL::Subscript.new(:co__conkey, [x]), x]}, 32, :att2__attnum)).
301:           select(:co__conname___name, :cl2__relname___table, :att2__attname___refcolumn)
302: 
303:         # If a schema is given, we only search in that schema, and the returned :table
304:         # entry is schema qualified as well.
305:         if schema
306:           ref_ds = ref_ds.join(:pg_namespace___nsp2, :oid=>:cl2__relnamespace).
307:             select_more(:nsp2__nspname___schema)
308:         end
309: 
310:         h = {}
311:         fklod_map = FOREIGN_KEY_LIST_ON_DELETE_MAP 
312:         ds.each do |row|
313:           if r = h[row[:name]]
314:             r[:columns] << m.call(row[:column])
315:           else
316:             h[row[:name]] = {:name=>m.call(row[:name]), :columns=>[m.call(row[:column])], :on_update=>fklod_map[row[:on_update]], :on_delete=>fklod_map[row[:on_delete]], :deferrable=>row[:deferrable]}
317:           end
318:         end
319:         ref_ds.each do |row|
320:           r = h[row[:name]]
321:           r[:table] ||= schema ? SQL::QualifiedIdentifier.new(m.call(row[:schema]), m.call(row[:table])) : m.call(row[:table])
322:           r[:key] ||= []
323:           r[:key] << m.call(row[:refcolumn])
324:         end
325:         h.values
326:       end

indexes(table, opts={})

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

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 329
329:       def indexes(table, opts={})
330:         m = output_identifier_meth
331:         range = 0...32
332:         attnums = server_version >= 80100 ? SQL::Function.new(:ANY, :ind__indkey) : range.map{|x| SQL::Subscript.new(:ind__indkey, [x])}
333:         ds = metadata_dataset.
334:           from(:pg_class___tab).
335:           join(:pg_index___ind, :indrelid=>:oid).
336:           join(:pg_class___indc, :oid=>:indexrelid).
337:           join(:pg_attribute___att, :attrelid=>:tab__oid, :attnum=>attnums).
338:           left_join(:pg_constraint___con, :conname=>:indc__relname).
339:           filter(:indc__relkind=>'i', :ind__indisprimary=>false, :indexprs=>nil, :indpred=>nil, :indisvalid=>true, :tab__oid=>regclass_oid(table, opts)).
340:           order(:indc__relname, SQL::CaseExpression.new(range.map{|x| [SQL::Subscript.new(:ind__indkey, [x]), x]}, 32, :att__attnum)).
341:           select(:indc__relname___name, :ind__indisunique___unique, :att__attname___column, :con__condeferrable___deferrable)
342: 
343:         ds.filter!(:indisready=>true, :indcheckxmin=>false) if server_version >= 80300
344: 
345:         indexes = {}
346:         ds.each do |r|
347:           i = indexes[m.call(r[:name])] ||= {:columns=>[], :unique=>r[:unique], :deferrable=>r[:deferrable]}
348:           i[:columns] << m.call(r[:column])
349:         end
350:         indexes
351:       end

locks()

Dataset containing all current database locks

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 354
354:       def locks
355:         dataset.from(:pg_class).join(:pg_locks, :relation=>:relfilenode).select(:pg_class__relname, Sequel::SQL::ColumnAll.new(:pg_locks))
356:       end

notify(channel, 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.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 364
364:       def notify(channel, opts={})
365:         sql = "NOTIFY "
366:         dataset.send(:identifier_append, sql, channel)
367:         if payload = opts[:payload]
368:           sql << ", "
369:           dataset.literal_append(sql, payload.to_s)
370:         end
371:         execute_ddl(sql, opts)
372:       end

primary_key(table, opts={})

Return primary key for the given table.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 375
375:       def primary_key(table, opts={})
376:         quoted_table = quote_schema_table(table)
377:         Sequel.synchronize{return @primary_keys[quoted_table] if @primary_keys.has_key?(quoted_table)}
378:         sql = "#{SELECT_PK_SQL} AND pg_class.oid = #{literal(regclass_oid(table, opts))}"
379:         value = fetch(sql).single_value
380:         Sequel.synchronize{@primary_keys[quoted_table] = value}
381:       end

primary_key_sequence(table, opts={})

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

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 384
384:       def primary_key_sequence(table, opts={})
385:         quoted_table = quote_schema_table(table)
386:         Sequel.synchronize{return @primary_key_sequences[quoted_table] if @primary_key_sequences.has_key?(quoted_table)}
387:         sql = "#{SELECT_SERIAL_SEQUENCE_SQL} AND t.oid = #{literal(regclass_oid(table, opts))}"
388:         if pks = fetch(sql).single_record
389:           value = literal(SQL::QualifiedIdentifier.new(pks[:schema], pks[:sequence]))
390:           Sequel.synchronize{@primary_key_sequences[quoted_table] = value}
391:         else
392:           sql = "#{SELECT_CUSTOM_SEQUENCE_SQL} AND t.oid = #{literal(regclass_oid(table, opts))}"
393:           if pks = fetch(sql).single_record
394:             value = literal(SQL::QualifiedIdentifier.new(pks[:schema], LiteralString.new(pks[:sequence])))
395:             Sequel.synchronize{@primary_key_sequences[quoted_table] = value}
396:           end
397:         end
398:       end

reset_conversion_procs()

Reset the database‘s conversion procs, requires a server query if there any named types.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 402
402:       def reset_conversion_procs
403:         @conversion_procs = get_conversion_procs
404:       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.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 408
408:       def reset_primary_key_sequence(table)
409:         return unless seq = primary_key_sequence(table)
410:         pk = SQL::Identifier.new(primary_key(table))
411:         db = self
412:         seq_ds = db.from(LiteralString.new(seq))
413:         s, t = schema_and_table(table)
414:         table = Sequel.qualify(s, t) if s
415:         get{setval(seq, db[table].select{coalesce(max(pk)+seq_ds.select{:increment_by}, seq_ds.select(:min_value))}, false)}
416:       end

rollback_prepared_transaction(transaction_id)

Rollback an existing prepared transaction with the given transaction identifier string.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 420
420:       def rollback_prepared_transaction(transaction_id)
421:         run("ROLLBACK PREPARED #{literal(transaction_id)}")
422:       end

serial_primary_key_options()

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

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 426
426:       def serial_primary_key_options
427:         {:primary_key => true, :serial => true, :type=>Integer}
428:       end

server_version(server=nil)

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

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 431
431:       def server_version(server=nil)
432:         return @server_version if @server_version
433:         @server_version = synchronize(server) do |conn|
434:           (conn.server_version rescue nil) if conn.respond_to?(:server_version)
435:         end
436:         unless @server_version
437:           @server_version = if m = /PostgreSQL (\d+)\.(\d+)(?:(?:rc\d+)|\.(\d+))?/.match(fetch('SELECT version()').single_value)
438:             (m[1].to_i * 10000) + (m[2].to_i * 100) + m[3].to_i
439:           else
440:             0
441:           end
442:         end
443:         warn 'Sequel no longer supports PostgreSQL <8.2, some things may not work' if @server_version < 80200
444:         @server_version
445:       end

supports_create_table_if_not_exists?()

PostgreSQL supports CREATE TABLE IF NOT EXISTS on 9.1+

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 448
448:       def supports_create_table_if_not_exists?
449:         server_version >= 90100
450:       end

supports_deferrable_constraints?()

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

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 453
453:       def supports_deferrable_constraints?
454:         server_version >= 90000
455:       end

supports_deferrable_foreign_key_constraints?()

PostgreSQL supports deferrable foreign key constraints.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 458
458:       def supports_deferrable_foreign_key_constraints?
459:         true
460:       end

supports_drop_table_if_exists?()

PostgreSQL supports DROP TABLE IF EXISTS

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 463
463:       def supports_drop_table_if_exists?
464:         true
465:       end

supports_prepared_transactions?()

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

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 469
469:       def supports_prepared_transactions?
470:         return @supports_prepared_transactions if defined?(@supports_prepared_transactions)
471:         @supports_prepared_transactions = self['SHOW max_prepared_transactions'].get.to_i > 0
472:       end

supports_savepoints?()

PostgreSQL supports savepoints

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 475
475:       def supports_savepoints?
476:         true
477:       end

supports_transaction_isolation_levels?()

PostgreSQL supports transaction isolation levels

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 480
480:       def supports_transaction_isolation_levels?
481:         true
482:       end

supports_transactional_ddl?()

PostgreSQL supports transaction DDL statements.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 485
485:       def supports_transactional_ddl?
486:         true
487:       end

tables(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

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 498
498:       def tables(opts={}, &block)
499:         pg_class_relname('r', opts, &block)
500:       end

type_supported?(type)

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

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 504
504:       def type_supported?(type)
505:         @supported_types ||= {}
506:         @supported_types.fetch(type){@supported_types[type] = (from(:pg_type).filter(:typtype=>'b', :typname=>type.to_s).count > 0)}
507:       end

views(opts={})

Array of symbols specifying view names in the current database.

Options:

: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

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 516
516:       def views(opts={})
517:         pg_class_relname('v', opts)
518:       end