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  [RW]  Whether infinite timestamps should be converted on retrieval. By default, no conversion is done, so an error is raised if you attempt to retrieve an infinite timestamp. 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 Class methods

Add the primary_keys and primary_key_sequences instance variables, so we can get the correct return values for inserted rows.

[Source]

     # File lib/sequel/adapters/postgres.rb, line 167
167:       def initialize(*args)
168:         super
169:         @convert_infinite_timestamps = false
170:         initialize_postgres_adapter
171:       end

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 177
177:       def bound_variable_arg(arg, conn)
178:         case arg
179:         when Sequel::SQL::Blob
180:           conn.escape_bytea(arg)
181:         when Sequel::SQLTime
182:           literal(arg)
183:         when DateTime, Time
184:           literal(arg)
185:         else
186:           arg
187:         end
188:       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 196
196:       def connect(server)
197:         opts = server_opts(server)
198:         conn = if SEQUEL_POSTGRES_USES_PG
199:           connection_params = {
200:             :host => opts[:host],
201:             :port => opts[:port] || 5432,
202:             :dbname => opts[:database],
203:             :user => opts[:user],
204:             :password => opts[:password],
205:             :connect_timeout => opts[:connect_timeout] || 20,
206:             :sslmode => opts[:sslmode]
207:           }.delete_if { |key, value| blank_object?(value) }
208:           Adapter.connect(connection_params)
209:         else
210:           Adapter.connect(
211:             (opts[:host] unless blank_object?(opts[:host])),
212:             opts[:port] || 5432,
213:             nil, '',
214:             opts[:database],
215:             opts[:user],
216:             opts[:password]
217:           )
218:         end
219:         if encoding = opts[:encoding] || opts[:charset]
220:           if conn.respond_to?(:set_client_encoding)
221:             conn.set_client_encoding(encoding)
222:           else
223:             conn.async_exec("set client_encoding to '#{encoding}'")
224:           end
225:         end
226:         conn.instance_variable_set(:@db, self)
227:         conn.instance_variable_set(:@prepared_statements, {}) if SEQUEL_POSTGRES_USES_PG
228:         connection_configuration_sqls.each{|sql| conn.execute(sql)}
229:         conn
230:       end

copy_table uses PostgreSQL‘s COPY 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 FROM+ or +COPY TO+ with a filename, you should just use run instead of this method. This method does not currently support +COPY FROM STDIN+, but that may be supported in the future.

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 264
264:         def copy_table(table, opts={})
265:           sql = if table.is_a?(String)
266:             sql = table
267:           else
268:             if opts[:options] || opts[:format]
269:               options = " ("
270:               options << "FORMAT #{opts[:format]}" if opts[:format]
271:               options << "#{', ' if opts[:format]}#{opts[:options]}" if opts[:options]
272:               options << ')'
273:             end
274:             table = if table.is_a?(::Sequel::Dataset)
275:               "(#{table.sql})"
276:             else
277:               literal(table)
278:             end
279:            sql = "COPY #{table} TO STDOUT#{options}"
280:           end
281:           synchronize(opts[:server]) do |conn| 
282:             conn.execute(sql)
283:             begin
284:               if block_given?
285:                 while buf = conn.get_copy_data
286:                   yield buf
287:                 end
288:                 nil
289:               else
290:                 b = ''
291:                 b << buf while buf = conn.get_copy_data
292:                 b
293:               end
294:             ensure
295:               raise DatabaseDisconnectError, "disconnecting as a partial COPY may leave the connection in an unusable state" if buf
296:             end
297:           end 
298:         end

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

[Source]

     # File lib/sequel/adapters/postgres.rb, line 233
233:       def execute(sql, opts={}, &block)
234:         synchronize(opts[:server]){|conn| check_database_errors{_execute(conn, sql, opts, &block)}}
235:       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 321
321:         def listen(channels, opts={}, &block)
322:           check_database_errors do
323:             synchronize(opts[:server]) do |conn|
324:               begin
325:                 channels = Array(channels)
326:                 channels.each{|channel| conn.execute("LISTEN #{channel}")}
327:                 opts[:after_listen].call(conn) if opts[:after_listen]
328:                 timeout = opts[:timeout] ? [opts[:timeout]] : []
329:                 if l = opts[:loop]
330:                   raise Error, 'calling #listen with :loop requires a block' unless block
331:                   loop_call = l.respond_to?(:call)
332:                   catch(:stop) do
333:                     loop do
334:                       conn.wait_for_notify(*timeout, &block)
335:                       l.call(conn) if loop_call
336:                     end
337:                   end
338:                   nil
339:                 else
340:                   conn.wait_for_notify(*timeout, &block)
341:                 end
342:               ensure
343:                 conn.execute("UNLISTEN *")
344:               end
345:             end
346:           end
347:         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 352
352:       def to_application_timestamp(value)
353:         if c = convert_infinite_timestamps
354:           case value
355:           when *INFINITE_TIMESTAMP_STRINGS
356:             infinite_timestamp_value(value)
357:           else
358:             super
359:           end
360:         else
361:           super
362:         end
363:       end

[Validate]