| Class | ActiveRecord::ConnectionAdapters::PostgreSQLAdapter |
| In: |
vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
|
| Parent: | AbstractAdapter |
The PostgreSQL adapter works both with the native C (ruby.scripting.ca/postgres/) and the pure Ruby (available both as gem and from rubyforge.org/frs/?group_id=234&release_id=1944) drivers.
Options:
Initializes and connects a PostgreSQL adapter.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 233
233: def initialize(connection, logger, connection_parameters, config)
234: super(connection, logger)
235: @connection_parameters, @config = connection_parameters, config
236:
237: connect
238: end
Is this connection alive and ready for queries?
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 241
241: def active?
242: if @connection.respond_to?(:status)
243: @connection.status == PGconn::CONNECTION_OK
244: else
245: # We're asking the driver, not ActiveRecord, so use @connection.query instead of #query
246: @connection.query 'SELECT 1'
247: true
248: end
249: # postgres-pr raises a NoMethodError when querying if no connection is available.
250: rescue PGError, NoMethodError
251: false
252: end
Returns ‘PostgreSQL’ as adapter name for identification purposes.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 228
228: def adapter_name
229: 'PostgreSQL'
230: end
Adds a column to a table.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 594
594: def add_column(table_name, column_name, type, options = {})
595: default = options[:default]
596: notnull = options[:null] == false
597:
598: # Add the column.
599: execute("ALTER TABLE #{table_name} ADD COLUMN #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit])}")
600:
601: change_column_default(table_name, column_name, default) if options_include_default?(options)
602: change_column_null(table_name, column_name, false, default) if notnull
603: end
Begins a transaction.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 422
422: def begin_db_transaction
423: execute "BEGIN"
424: end
Changes the column of a table.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 606
606: def change_column(table_name, column_name, type, options = {})
607: begin
608: execute "ALTER TABLE #{table_name} ALTER COLUMN #{quote_column_name(column_name)} TYPE #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
609: rescue ActiveRecord::StatementInvalid
610: # This is PostgreSQL 7.x, so we have to use a more arcane way of doing it.
611: begin_db_transaction
612: tmp_column_name = "#{column_name}_ar_tmp"
613: add_column(table_name, tmp_column_name, type, options)
614: execute "UPDATE #{table_name} SET #{quote_column_name(tmp_column_name)} = CAST(#{quote_column_name(column_name)} AS #{type_to_sql(type, options[:limit], options[:precision], options[:scale])})"
615: remove_column(table_name, column_name)
616: rename_column(table_name, tmp_column_name, column_name)
617: commit_db_transaction
618: end
619:
620: change_column_default(table_name, column_name, options[:default]) if options_include_default?(options)
621: change_column_null(table_name, column_name, options[:null], options[:default]) if options.key?(:null)
622: end
Changes the default value of a table column.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 625
625: def change_column_default(table_name, column_name, default)
626: execute "ALTER TABLE #{table_name} ALTER COLUMN #{quote_column_name(column_name)} SET DEFAULT #{quote(default)}"
627: end
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 629
629: def change_column_null(table_name, column_name, null, default = nil)
630: unless null || default.nil?
631: execute("UPDATE #{table_name} SET #{quote_column_name(column_name)}=#{quote(default)} WHERE #{quote_column_name(column_name)} IS NULL")
632: end
633: execute("ALTER TABLE #{table_name} ALTER #{quote_column_name(column_name)} #{null ? 'DROP' : 'SET'} NOT NULL")
634: end
Returns the current client message level.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 510
510: def client_min_messages
511: query('SHOW client_min_messages')[0][0]
512: end
Set the client message level.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 515
515: def client_min_messages=(level)
516: execute("SET client_min_messages TO '#{level}'")
517: end
Returns the list of all column definitions for a table.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 485
485: def columns(table_name, name = nil)
486: # Limit, precision, and scale are all handled by the superclass.
487: column_definitions(table_name).collect do |name, type, default, notnull|
488: PostgreSQLColumn.new(name, default, type, notnull == 'f')
489: end
490: end
Commits a transaction.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 427
427: def commit_db_transaction
428: execute "COMMIT"
429: end
Close the connection.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 266
266: def disconnect!
267: @connection.close rescue nil
268: end
Executes an SQL statement, returning a PGresult object on success or raising a PGError exception otherwise.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 406
406: def execute(sql, name = nil)
407: log(sql, name) do
408: if @async
409: @connection.async_exec(sql)
410: else
411: @connection.exec(sql)
412: end
413: end
414: end
Returns the list of all indexes for a table.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 450
450: def indexes(table_name, name = nil)
451: result = query("SELECT i.relname, d.indisunique, a.attname\nFROM pg_class t, pg_class i, pg_index d, pg_attribute a\nWHERE i.relkind = 'i'\nAND d.indexrelid = i.oid\nAND d.indisprimary = 'f'\nAND t.oid = d.indrelid\nAND t.relname = '\#{table_name}'\nAND a.attrelid = t.oid\nAND ( d.indkey[0]=a.attnum OR d.indkey[1]=a.attnum\nOR d.indkey[2]=a.attnum OR d.indkey[3]=a.attnum\nOR d.indkey[4]=a.attnum OR d.indkey[5]=a.attnum\nOR d.indkey[6]=a.attnum OR d.indkey[7]=a.attnum\nOR d.indkey[8]=a.attnum OR d.indkey[9]=a.attnum )\nORDER BY i.relname\n", name)
452:
453: current_index = nil
454: indexes = []
455:
456: result.each do |row|
457: if current_index != row[0]
458: indexes << IndexDefinition.new(table_name, row[0], row[1] == "t", [])
459: current_index = row[0]
460: end
461:
462: indexes.last.columns << row[2]
463: end
464:
465: indexes
466: end
Executes an INSERT query and returns the new record‘s ID
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 388
388: def insert(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)
389: table = sql.split(" ", 4)[2]
390: super || last_insert_id(table, sequence_name || default_sequence_name(table, pk))
391: end
Close then reopen the connection.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 255
255: def reconnect!
256: if @connection.respond_to?(:reset)
257: @connection.reset
258: configure_connection
259: else
260: disconnect!
261: connect
262: end
263: end
Drops an index from a table.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 642
642: def remove_index(table_name, options = {})
643: execute "DROP INDEX #{index_name(table_name, options)}"
644: end
Renames a column in a table.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 637
637: def rename_column(table_name, column_name, new_column_name)
638: execute "ALTER TABLE #{table_name} RENAME COLUMN #{quote_column_name(column_name)} TO #{quote_column_name(new_column_name)}"
639: end
Renames a table.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 589
589: def rename_table(name, new_name)
590: execute "ALTER TABLE #{name} RENAME TO #{new_name}"
591: end
Aborts a transaction.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 432
432: def rollback_db_transaction
433: execute "ROLLBACK"
434: end
Returns the active schema search path.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 505
505: def schema_search_path
506: @schema_search_path ||= query('SHOW search_path')[0][0]
507: end
Sets the schema search path to a string of comma-separated schema names. Names beginning with $ have to be quoted (e.g. $user => ’$user’). See: www.postgresql.org/docs/current/static/ddl-schemas.html
This should be not be called manually but set in database.yml.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 497
497: def schema_search_path=(schema_csv)
498: if schema_csv
499: execute "SET search_path TO #{schema_csv}"
500: @schema_search_path = schema_csv
501: end
502: end
Executes a SELECT query and returns an array of rows. Each row is an array of field values.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 383
383: def select_rows(sql, name = nil)
384: select_raw(sql, name).last
385: end
Does PostgreSQL support migrations?
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 288
288: def supports_migrations?
289: true
290: end
Does PostgreSQL support standard conforming strings?
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 293
293: def supports_standard_conforming_strings?
294: # Temporarily set the client message level above error to prevent unintentional
295: # error messages in the logs when working on a PostgreSQL database server that
296: # does not support standard conforming strings.
297: client_min_messages_old = client_min_messages
298: self.client_min_messages = 'panic'
299:
300: # postgres-pr does not raise an exception when client_min_messages is set higher
301: # than error and "SHOW standard_conforming_strings" fails, but returns an empty
302: # PGresult instead.
303: has_support = execute('SHOW standard_conforming_strings')[0][0] rescue false
304: self.client_min_messages = client_min_messages_old
305: has_support
306: end
Returns the configured supported identifier length supported by PostgreSQL, or report the default of 63 on PostgreSQL 7.x.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 310
310: def table_alias_length
311: @table_alias_length ||= (postgresql_version >= 80000 ? query('SHOW max_identifier_length')[0][0].to_i : 63)
312: end
Returns the list of all tables in the schema search path or a specified schema.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 439
439: def tables(name = nil)
440: schemas = schema_search_path.split(/,/).map { |p| quote(p) }.join(',')
441: query("SELECT tablename\nFROM pg_tables\nWHERE schemaname IN (\#{schemas})\n", name).map { |row| row[0] }
442: end
Maps logical Rails types to PostgreSQL-specific data types.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 647
647: def type_to_sql(type, limit = nil, precision = nil, scale = nil)
648: return super unless type.to_s == 'integer'
649:
650: if limit.nil? || limit == 4
651: 'integer'
652: elsif limit < 4
653: 'smallint'
654: else
655: 'bigint'
656: end
657: end
Executes an UPDATE query and returns the number of affected tuples.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 417
417: def update_sql(sql, name = nil)
418: super.cmdtuples
419: end
Returns the version of the connected PostgreSQL version.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 696
696: def postgresql_version
697: @postgresql_version ||=
698: if @connection.respond_to?(:server_version)
699: @connection.server_version
700: else
701: # Mimic PGconn.server_version behavior
702: begin
703: query('SELECT version()')[0][0] =~ /PostgreSQL (\d+)\.(\d+)\.(\d+)/
704: ($1.to_i * 10000) + ($2.to_i * 100) + $3.to_i
705: rescue
706: 0
707: end
708: end
709: end