Module Sequel::Postgres::DatabaseMethods
In: lib/sequel/adapters/shared/postgres.rb

Methods shared by Database instances that connect to PostgreSQL.

Methods

Constants

PREPARED_ARG_PLACEHOLDER = LiteralString.new('$').freeze
RE_CURRVAL_ERROR = /currval of sequence "(.*)" is not yet defined in this session|relation "(.*)" does not exist/.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
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(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
DEADLOCK_SQL_STATE = '40P01'.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 an existing prepared transaction with the given transaction identifier string.

[Source]

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

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.
: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 186
186:       def create_function(name, definition, opts=OPTS)
187:         self << create_function_sql(name, definition, opts)
188:       end

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 197
197:       def create_language(name, opts=OPTS)
198:         self << create_language_sql(name, opts)
199:       end

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)

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 206
206:       def create_schema(name, opts=OPTS)
207:         self << create_schema_sql(name, opts)
208:       end

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.
:when :A filter to use for the trigger

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 221
221:       def create_trigger(table, name, function, opts=OPTS)
222:         self << create_trigger_sql(table, name, function, opts)
223:       end

PostgreSQL uses the :postgres database type.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 226
226:       def database_type
227:         :postgres
228:       end

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 235
235:       def do(code, opts=OPTS)
236:         language = opts[:language]
237:         run "DO #{"LANGUAGE #{literal(language.to_s)} " if language}#{literal(code)}"
238:       end

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 246
246:       def drop_function(name, opts=OPTS)
247:         self << drop_function_sql(name, opts)
248:       end

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 255
255:       def drop_language(name, opts=OPTS)
256:         self << drop_language_sql(name, opts)
257:       end

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 264
264:       def drop_schema(name, opts=OPTS)
265:         self << drop_schema_sql(name, opts)
266:       end

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 274
274:       def drop_trigger(table, name, opts=OPTS)
275:         self << drop_trigger_sql(table, name, opts)
276:       end

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

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

[Source]

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

Dataset containing all current database locks

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 359
359:       def locks
360:         dataset.from(:pg_class).join(:pg_locks, :relation=>:relfilenode).select(:pg_class__relname, Sequel::SQL::ColumnAll.new(:pg_locks))
361:       end

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 369
369:       def notify(channel, opts=OPTS)
370:         sql = "NOTIFY "
371:         dataset.send(:identifier_append, sql, channel)
372:         if payload = opts[:payload]
373:           sql << ", "
374:           dataset.literal_append(sql, payload.to_s)
375:         end
376:         execute_ddl(sql, opts)
377:       end

Return primary key for the given table.

[Source]

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

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

[Source]

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

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

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 411
411:       def refresh_view(name, opts=OPTS)
412:         run "REFRESH MATERIALIZED VIEW#{' CONCURRENTLY' if opts[:concurrently]} #{quote_schema_table(name)}"
413:       end

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

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 417
417:       def reset_conversion_procs
418:         @conversion_procs = get_conversion_procs
419:         conversion_procs_updated
420:         @conversion_procs
421:       end

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 425
425:       def reset_primary_key_sequence(table)
426:         return unless seq = primary_key_sequence(table)
427:         pk = SQL::Identifier.new(primary_key(table))
428:         db = self
429:         seq_ds = db.from(LiteralString.new(seq))
430:         s, t = schema_and_table(table)
431:         table = Sequel.qualify(s, t) if s
432:         get{setval(seq, db[table].select{coalesce(max(pk)+seq_ds.select{:increment_by}, seq_ds.select(:min_value))}, false)}
433:       end

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

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 437
437:       def rollback_prepared_transaction(transaction_id, opts=OPTS)
438:         run("ROLLBACK PREPARED #{literal(transaction_id)}", opts)
439:       end

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

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 443
443:       def serial_primary_key_options
444:         {:primary_key => true, :serial => true, :type=>Integer}
445:       end

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

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 448
448:       def server_version(server=nil)
449:         return @server_version if @server_version
450:         @server_version = synchronize(server) do |conn|
451:           (conn.server_version rescue nil) if conn.respond_to?(:server_version)
452:         end
453:         unless @server_version
454:           @server_version = if m = /PostgreSQL (\d+)\.(\d+)(?:(?:rc\d+)|\.(\d+))?/.match(fetch('SELECT version()').single_value)
455:             (m[1].to_i * 10000) + (m[2].to_i * 100) + m[3].to_i
456:           else
457:             0
458:           end
459:         end
460:         warn 'Sequel no longer supports PostgreSQL <8.2, some things may not work' if @server_version < 80200
461:         @server_version
462:       end

PostgreSQL supports CREATE TABLE IF NOT EXISTS on 9.1+

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 465
465:       def supports_create_table_if_not_exists?
466:         server_version >= 90100
467:       end

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

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 470
470:       def supports_deferrable_constraints?
471:         server_version >= 90000
472:       end

PostgreSQL supports deferrable foreign key constraints.

[Source]

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

PostgreSQL supports DROP TABLE IF EXISTS

[Source]

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

PostgreSQL supports partial indexes.

[Source]

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

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

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 496
496:       def supports_prepared_transactions?
497:         return @supports_prepared_transactions if defined?(@supports_prepared_transactions)
498:         @supports_prepared_transactions = self['SHOW max_prepared_transactions'].get.to_i > 0
499:       end

PostgreSQL supports savepoints

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 502
502:       def supports_savepoints?
503:         true
504:       end

PostgreSQL supports transaction isolation levels

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 507
507:       def supports_transaction_isolation_levels?
508:         true
509:       end

PostgreSQL supports transaction DDL statements.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 512
512:       def supports_transactional_ddl?
513:         true
514:       end

PostgreSQL 9.0+ supports trigger conditions.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 490
490:       def supports_trigger_conditions?
491:         server_version >= 90000
492:       end

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 525
525:       def tables(opts=OPTS, &block)
526:         pg_class_relname('r', opts, &block)
527:       end

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 531
531:       def type_supported?(type)
532:         @supported_types ||= {}
533:         @supported_types.fetch(type){@supported_types[type] = (from(:pg_type).filter(:typtype=>'b', :typname=>type.to_s).count > 0)}
534:       end

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

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 543
543:       def values(v)
544:         @default_dataset.clone(:values=>v)
545:       end

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 554
554:       def views(opts=OPTS)
555:         pg_class_relname('v', opts)
556:       end

[Validate]