Class Sequel::Postgres::Database
In: lib/sequel/adapters/postgres.rb
Parent: Sequel::Database

Database class for PostgreSQL databases used with Sequel and the pg, postgres, or postgres-pr driver.

Methods

Included Modules

Sequel::Postgres::DatabaseMethods

Constants

INFINITE_TIMESTAMP_STRINGS = ['infinity'.freeze, '-infinity'.freeze].freeze
INFINITE_DATETIME_VALUES = ([PLUS_INFINITY, MINUS_INFINITY] + INFINITE_TIMESTAMP_STRINGS).freeze

Attributes

convert_infinite_timestamps  [R]  Whether infinite timestamps/dates should be converted on retrieval. By default, no conversion is done, so an error is raised if you attempt to retrieve an infinite timestamp/date. You can set this to :nil to convert to nil, :string to leave as a string, or :float to convert to an infinite float.

Public Instance methods

Convert given argument so that it can be used directly by pg. Currently, pg doesn‘t handle fractional seconds in Time/DateTime or blobs with "\0", and it won‘t ever handle Sequel::SQLTime values correctly. Only public for use by the adapter, shouldn‘t be used by external code.

[Source]

     # File lib/sequel/adapters/postgres.rb, line 185
185:       def bound_variable_arg(arg, conn)
186:         case arg
187:         when Sequel::SQL::Blob
188:           conn.escape_bytea(arg)
189:         when Sequel::SQLTime
190:           literal(arg)
191:         when DateTime, Time
192:           literal(arg)
193:         else
194:           arg
195:         end
196:       end

Connects to the database. In addition to the standard database options, using the :encoding or :charset option changes the client encoding for the connection, :connect_timeout is a connection timeout in seconds, and :sslmode sets whether postgres‘s sslmode. :connect_timeout and :ssl_mode are only supported if the pg driver is used.

[Source]

     # File lib/sequel/adapters/postgres.rb, line 204
204:       def connect(server)
205:         opts = server_opts(server)
206:         conn = if SEQUEL_POSTGRES_USES_PG
207:           connection_params = {
208:             :host => opts[:host],
209:             :port => opts[:port] || 5432,
210:             :dbname => opts[:database],
211:             :user => opts[:user],
212:             :password => opts[:password],
213:             :connect_timeout => opts[:connect_timeout] || 20,
214:             :sslmode => opts[:sslmode]
215:           }.delete_if { |key, value| blank_object?(value) }
216:           Adapter.connect(connection_params)
217:         else
218:           Adapter.connect(
219:             (opts[:host] unless blank_object?(opts[:host])),
220:             opts[:port] || 5432,
221:             nil, '',
222:             opts[:database],
223:             opts[:user],
224:             opts[:password]
225:           )
226:         end
227:         if encoding = opts[:encoding] || opts[:charset]
228:           if conn.respond_to?(:set_client_encoding)
229:             conn.set_client_encoding(encoding)
230:           else
231:             conn.async_exec("set client_encoding to '#{encoding}'")
232:           end
233:         end
234:         conn.instance_variable_set(:@db, self)
235:         conn.instance_variable_set(:@prepared_statements, {}) if SEQUEL_POSTGRES_USES_PG
236:         connection_configuration_sqls.each{|sql| conn.execute(sql)}
237:         conn
238:       end

Set whether to allow infinite timestamps/dates. Make sure the conversion proc for date reflects that setting.

[Source]

     # File lib/sequel/adapters/postgres.rb, line 242
242:       def convert_infinite_timestamps=(v)
243:         @convert_infinite_timestamps = case v
244:         when Symbol
245:           v
246:         when 'nil'
247:           :nil
248:         when 'string'
249:           :string
250:         when 'float'
251:           :float
252:         when String
253:           typecast_value_boolean(v)
254:         else
255:           false
256:         end
257: 
258:         pr = old_pr = @use_iso_date_format ? TYPE_TRANSLATOR.method(:date) : Sequel.method(:string_to_date)
259:         if v
260:           pr = lambda do |val|
261:             case val
262:             when *INFINITE_TIMESTAMP_STRINGS
263:               infinite_timestamp_value(val)
264:             else
265:               old_pr.call(val)
266:             end
267:           end
268:         end
269:         conversion_procs[1082] = pr
270:       end

copy_into uses PostgreSQL‘s +COPY FROM STDIN+ SQL statement to do very fast inserts into a table using input preformatting in either CSV or PostgreSQL text format. This method is only supported if pg 0.14.0+ is the underlying ruby driver. This method should only be called if you want results returned to the client. If you are using +COPY FROM+ with a filename, you should just use run instead of this method.

The following options are respected:

:columns :The columns to insert into, with the same order as the columns in the input data. If this isn‘t given, uses all columns in the table.
:data :The data to copy to PostgreSQL, which should already be in CSV or PostgreSQL text format. This can be either a string, or any object that responds to each and yields string.
:format :The format to use. text is the default, so this should be :csv or :binary.
:options :An options SQL string to use, which should contain comma separated options.
:server :The server on which to run the query.

If a block is provided and :data option is not, this will yield to the block repeatedly. The block should return a string, or nil to signal that it is finished.

[Source]

     # File lib/sequel/adapters/postgres.rb, line 375
375:         def copy_into(table, opts=OPTS)
376:           data = opts[:data]
377:           data = Array(data) if data.is_a?(String)
378: 
379:           if block_given? && data
380:             raise Error, "Cannot provide both a :data option and a block to copy_into"
381:           elsif !block_given? && !data
382:             raise Error, "Must provide either a :data option or a block to copy_into"
383:           end
384: 
385:           synchronize(opts[:server]) do |conn|
386:             conn.execute(copy_into_sql(table, opts))
387:             begin
388:               if block_given?
389:                 while buf = yield
390:                   conn.put_copy_data(buf)
391:                 end
392:               else
393:                 data.each{|buff| conn.put_copy_data(buff)}
394:               end
395:             rescue Exception => e
396:               conn.put_copy_end("ruby exception occurred while copying data into PostgreSQL")
397:             ensure
398:               conn.put_copy_end unless e
399:               while res = conn.get_result
400:                 raise e if e
401:                 check_database_errors{res.check}
402:               end
403:             end
404:           end 
405:         end

copy_table uses PostgreSQL‘s +COPY TO STDOUT+ SQL statement to return formatted results directly to the caller. This method is only supported if pg is the underlying ruby driver. This method should only be called if you want results returned to the client. If you are using +COPY TO+ with a filename, you should just use run instead of this method.

The table argument supports the following types:

String :Uses the first argument directly as literal SQL. If you are using a version of PostgreSQL before 9.0, you will probably want to use a string if you are using any options at all, as the syntax Sequel uses for options is only compatible with PostgreSQL 9.0+.
Dataset :Uses a query instead of a table name when copying.
other :Uses a table name (usually a symbol) when copying.

The following options are respected:

:format :The format to use. text is the default, so this should be :csv or :binary.
:options :An options SQL string to use, which should contain comma separated options.
:server :The server on which to run the query.

If a block is provided, the method continually yields to the block, one yield per row. If a block is not provided, a single string is returned with all of the data.

[Source]

     # File lib/sequel/adapters/postgres.rb, line 335
335:         def copy_table(table, opts=OPTS)
336:           synchronize(opts[:server]) do |conn|
337:             conn.execute(copy_table_sql(table, opts))
338:             begin
339:               if block_given?
340:                 while buf = conn.get_copy_data
341:                   yield buf
342:                 end
343:                 nil
344:               else
345:                 b = ''
346:                 b << buf while buf = conn.get_copy_data
347:                 b
348:               end
349:             ensure
350:               raise DatabaseDisconnectError, "disconnecting as a partial COPY may leave the connection in an unusable state" if buf
351:             end
352:           end 
353:         end

Disconnect given connection

[Source]

     # File lib/sequel/adapters/postgres.rb, line 273
273:       def disconnect_connection(conn)
274:         begin
275:           conn.finish
276:         rescue PGError, IOError
277:         end
278:       end

Return a hash of information about the related PGError (or Sequel::DatabaseError that wraps a PGError), with the following entries:

:schema :The schema name related to the error
:table :The table name related to the error
:column :the column name related to the error
:constraint :The constraint name related to the error
:type :The datatype name related to the error

This requires a PostgreSQL 9.3+ server and 9.3+ client library, and ruby-pg 0.16.0+ to be supported.

[Source]

     # File lib/sequel/adapters/postgres.rb, line 292
292:         def error_info(e)
293:           e = e.wrapped_exception if e.is_a?(DatabaseError)
294:           r = e.result
295:           h = {}
296:           h[:schema] = r.error_field(::PG::PG_DIAG_SCHEMA_NAME)
297:           h[:table] = r.error_field(::PG::PG_DIAG_TABLE_NAME)
298:           h[:column] = r.error_field(::PG::PG_DIAG_COLUMN_NAME)
299:           h[:constraint] = r.error_field(::PG::PG_DIAG_CONSTRAINT_NAME)
300:           h[:type] = r.error_field(::PG::PG_DIAG_DATATYPE_NAME)
301:           h
302:         end

Execute the given SQL with the given args on an available connection.

[Source]

     # File lib/sequel/adapters/postgres.rb, line 306
306:       def execute(sql, opts=OPTS, &block)
307:         synchronize(opts[:server]){|conn| check_database_errors{_execute(conn, sql, opts, &block)}}
308:       end

Listens on the given channel (or multiple channels if channel is an array), waiting for notifications. After a notification is received, or the timeout has passed, stops listening to the channel. Options:

:after_listen :An object that responds to call that is called with the underlying connection after the LISTEN statement is sent, but before the connection starts waiting for notifications.
:loop :Whether to continually wait for notifications, instead of just waiting for a single notification. If this option is given, a block must be provided. If this object responds to call, it is called with the underlying connection after each notification is received (after the block is called). If a :timeout option is used, and a callable object is given, the object will also be called if the timeout expires. If :loop is used and you want to stop listening, you can either break from inside the block given to listen, or you can throw :stop from inside the :loop object‘s call method or the block.
:server :The server on which to listen, if the sharding support is being used.
:timeout :How long to wait for a notification, in seconds (can provide a float value for fractional seconds). If not given or nil, waits indefinitely.

This method is only supported if pg is used as the underlying ruby driver. It returns the channel the notification was sent to (as a string), unless :loop was used, in which case it returns nil. If a block is given, it is yielded 3 arguments:

  • the channel the notification was sent to (as a string)
  • the backend pid of the notifier (as an integer),
  • and the payload of the notification (as a string or nil).

[Source]

     # File lib/sequel/adapters/postgres.rb, line 428
428:         def listen(channels, opts=OPTS, &block)
429:           check_database_errors do
430:             synchronize(opts[:server]) do |conn|
431:               begin
432:                 channels = Array(channels)
433:                 channels.each do |channel|
434:                   sql = "LISTEN "
435:                   dataset.send(:identifier_append, sql, channel)
436:                   conn.execute(sql)
437:                 end
438:                 opts[:after_listen].call(conn) if opts[:after_listen]
439:                 timeout = opts[:timeout] ? [opts[:timeout]] : []
440:                 if l = opts[:loop]
441:                   raise Error, 'calling #listen with :loop requires a block' unless block
442:                   loop_call = l.respond_to?(:call)
443:                   catch(:stop) do
444:                     loop do
445:                       conn.wait_for_notify(*timeout, &block)
446:                       l.call(conn) if loop_call
447:                     end
448:                   end
449:                   nil
450:                 else
451:                   conn.wait_for_notify(*timeout, &block)
452:                 end
453:               ensure
454:                 conn.execute("UNLISTEN *")
455:               end
456:             end
457:           end
458:         end

If convert_infinite_timestamps is true and the value is infinite, return an appropriate value based on the convert_infinite_timestamps setting.

[Source]

     # File lib/sequel/adapters/postgres.rb, line 463
463:       def to_application_timestamp(value)
464:         if convert_infinite_timestamps
465:           case value
466:           when *INFINITE_TIMESTAMP_STRINGS
467:             infinite_timestamp_value(value)
468:           else
469:             super
470:           end
471:         else
472:           super
473:         end
474:       end

[Validate]