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

bound_variable_arg connect copy_table execute listen new to_application_timestamp

### 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

new(*args)

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

bound_variable_arg(arg, conn)

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

connect(server)

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(table, opts={}) {|buf| ...}

`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(sql, opts={}, &block)

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

listen(channels, opts={}, &block)

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

to_application_timestamp(value)

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]