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 C-based (www.postgresql.jp/interfaces/ruby/) and the Ruby-base (available both as gem and from rubyforge.org/frs/?group_id=234&release_id=1145) drivers.
Options:
BYTEA_COLUMN_TYPE_OID | = | 17 |
NUMERIC_COLUMN_TYPE_OID | = | 1700 |
TIMESTAMPOID | = | 1114 |
TIMESTAMPTZOID | = | 1184 |
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 55 55: def initialize(connection, logger, config = {}) 56: super(connection, logger) 57: @config = config 58: @async = config[:allow_concurrency] 59: configure_connection 60: end
Is this connection alive and ready for queries?
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 63 63: def active? 64: if @connection.respond_to?(:status) 65: @connection.status == PGconn::CONNECTION_OK 66: else 67: @connection.query 'SELECT 1' 68: true 69: end 70: # postgres-pr raises a NoMethodError when querying if no conn is available 71: rescue PGError, NoMethodError 72: false 73: end
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 51 51: def adapter_name 52: 'PostgreSQL' 53: end
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 321 321: def add_column(table_name, column_name, type, options = {}) 322: default = options[:default] 323: notnull = options[:null] == false 324: 325: # Add the column. 326: execute("ALTER TABLE #{table_name} ADD COLUMN #{column_name} #{type_to_sql(type, options[:limit])}") 327: 328: # Set optional default. If not null, update nulls to the new default. 329: if options_include_default?(options) 330: change_column_default(table_name, column_name, default) 331: if notnull 332: execute("UPDATE #{table_name} SET #{column_name}=#{quote(default, options[:column])} WHERE #{column_name} IS NULL") 333: end 334: end 335: 336: if notnull 337: execute("ALTER TABLE #{table_name} ALTER #{column_name} SET NOT NULL") 338: end 339: end
ORDER BY clause for the passed order option.
PostgreSQL does not allow arbitrary ordering when using DISTINCT ON, so we work around this by wrapping the sql as a sub-select and ordering in that query.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 408 408: def add_order_by_for_association_limiting!(sql, options) 409: return sql if options[:order].blank? 410: 411: order = options[:order].split(',').collect { |s| s.strip }.reject(&:blank?) 412: order.map! { |s| 'DESC' if s =~ /\bdesc$/i } 413: order = order.zip((0...order.size).to_a).map { |s,i| "id_list.alias_#{i} #{s}" }.join(', ') 414: 415: sql.replace "SELECT * FROM (#{sql}) AS id_list ORDER BY #{order}" 416: end
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 245 245: def default_sequence_name(table_name, pk = nil) 246: default_pk, default_seq = pk_and_sequence_for(table_name) 247: default_seq || "#{table_name}_#{pk || default_pk || 'id'}_seq" 248: end
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 84 84: def disconnect! 85: # Both postgres and postgres-pr respond to :close 86: @connection.close rescue nil 87: end
SELECT DISTINCT clause for a given set of columns and a given ORDER BY clause.
PostgreSQL requires the ORDER BY columns in the select list for distinct queries, and requires that the ORDER BY include the distinct column.
distinct("posts.id", "posts.created_at desc")
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 389 389: def distinct(columns, order_by) 390: return "DISTINCT #{columns}" if order_by.blank? 391: 392: # construct a clean list of column names from the ORDER BY clause, removing 393: # any asc/desc modifiers 394: order_columns = order_by.split(',').collect { |s| s.split.first } 395: order_columns.delete_if &:blank? 396: order_columns = order_columns.zip((0...order_columns.size).to_a).map { |s,i| "#{s} AS alias_#{i}" } 397: 398: # return a DISTINCT ON() clause that's distinct on the columns we want but includes 399: # all the required columns for the ORDER BY to work properly 400: sql = "DISTINCT ON (#{columns}) #{columns}, " 401: sql << order_columns * ', ' 402: end
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 89 89: def native_database_types 90: { 91: :primary_key => "serial primary key", 92: :string => { :name => "character varying", :limit => 255 }, 93: :text => { :name => "text" }, 94: :integer => { :name => "integer" }, 95: :float => { :name => "float" }, 96: :decimal => { :name => "decimal" }, 97: :datetime => { :name => "timestamp" }, 98: :timestamp => { :name => "timestamp" }, 99: :time => { :name => "time" }, 100: :date => { :name => "date" }, 101: :binary => { :name => "bytea" }, 102: :boolean => { :name => "boolean" } 103: } 104: end
Find a table‘s primary key and sequence.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 270 270: def pk_and_sequence_for(table) 271: # First try looking for a sequence with a dependency on the 272: # given table's primary key. 273: result = query("SELECT attr.attname, name.nspname, seq.relname\nFROM pg_class seq,\npg_attribute attr,\npg_depend dep,\npg_namespace name,\npg_constraint cons\nWHERE seq.oid = dep.objid\nAND seq.relnamespace = name.oid\nAND seq.relkind = 'S'\nAND attr.attrelid = dep.refobjid\nAND attr.attnum = dep.refobjsubid\nAND attr.attrelid = cons.conrelid\nAND attr.attnum = cons.conkey[1]\nAND cons.contype = 'p'\nAND dep.refobjid = '\#{table}'::regclass\n", 'PK and serial sequence')[0] 274: 275: if result.nil? or result.empty? 276: # If that fails, try parsing the primary key's default value. 277: # Support the 7.x and 8.0 nextval('foo'::text) as well as 278: # the 8.1+ nextval('foo'::regclass). 279: # TODO: assumes sequence is in same schema as table. 280: result = query("SELECT attr.attname, name.nspname, split_part(def.adsrc, '''', 2)\nFROM pg_class t\nJOIN pg_namespace name ON (t.relnamespace = name.oid)\nJOIN pg_attribute attr ON (t.oid = attrelid)\nJOIN pg_attrdef def ON (adrelid = attrelid AND adnum = attnum)\nJOIN pg_constraint cons ON (conrelid = adrelid AND adnum = conkey[1])\nWHERE t.oid = '\#{table}'::regclass\nAND cons.contype = 'p'\nAND def.adsrc ~* 'nextval'\n", 'PK and custom sequence')[0] 281: end 282: # check for existence of . in sequence name as in public.foo_sequence. if it does not exist, return unqualified sequence 283: # We cannot qualify unqualified sequences, as rails doesn't qualify any table access, using the search path 284: [result.first, result.last] 285: rescue 286: nil 287: end
QUOTING ==================================================
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 116 116: def quote(value, column = nil) 117: if value.kind_of?(String) && column && column.type == :binary 118: "'#{escape_bytea(value)}'" 119: else 120: super 121: end 122: end
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 124 124: def quote_column_name(name) 125: %("#{name}") 126: end
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 128 128: def quoted_date(value) 129: value.strftime("%Y-%m-%d %H:%M:%S.#{sprintf("%06d", value.usec)}") 130: end
Close then reopen the connection.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 76 76: def reconnect! 77: # TODO: postgres-pr doesn't have PGconn#reset. 78: if @connection.respond_to?(:reset) 79: @connection.reset 80: configure_connection 81: end 82: end
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 317 317: def rename_table(name, new_name) 318: execute "ALTER TABLE #{name} RENAME TO #{new_name}" 319: end
Resets sequence to the max value of the table‘s pk if present.
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 251 251: def reset_pk_sequence!(table, pk = nil, sequence = nil) 252: unless pk and sequence 253: default_pk, default_sequence = pk_and_sequence_for(table) 254: pk ||= default_pk 255: sequence ||= default_sequence 256: end 257: if pk 258: if sequence 259: select_value "SELECT setval('\#{sequence}', (SELECT COALESCE(MAX(\#{pk})+(SELECT increment_by FROM \#{sequence}), (SELECT min_value FROM \#{sequence})) FROM \#{table}), false)\n", 'Reset sequence' 260: else 261: @logger.warn "#{table} has primary key #{pk} with no default sequence" if @logger 262: end 263: end 264: end
# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 106 106: def supports_migrations? 107: true 108: end