Database class for PostgreSQL databases used with Sequel and the pg, postgres, or postgres-pr driver.
Connects to the database. In addition to the standard database options, using the :encoding or :charset option changes the client encoding for the connection.
# File lib/sequel/adapters/postgres.rb, line 219 def connect(server) opts = server_opts(server) conn = if SEQUEL_POSTGRES_USES_PG connection_params = { :host => opts[:host], :port => opts[:port] || 5432, :tty => '', :dbname => opts[:database], :user => opts[:user], :password => opts[:password], :connect_timeout => opts[:connect_timeout] || 20 }.delete_if { |key, value| blank_object?(value) } Adapter.connect(connection_params) else Adapter.connect( (opts[:host] unless blank_object?(opts[:host])), opts[:port] || 5432, nil, '', opts[:database], opts[:user], opts[:password] ) end if encoding = opts[:encoding] || opts[:charset] if conn.respond_to?(:set_client_encoding) conn.set_client_encoding(encoding) else conn.async_exec("set client_encoding to '#{encoding}'") end end conn.db = self conn.apply_connection_settings @conversion_procs ||= get_conversion_procs(conn) conn 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:
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+. | |
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.
# File lib/sequel/adapters/postgres.rb, line 302 def copy_table(table, opts={}) sql = if table.is_a?(String) sql = table else if opts[:options] || opts[:format] options = " (" options << "FORMAT #{opts[:format]}" if opts[:format] options << "#{', ' if opts[:format]}#{opts[:options]}" if opts[:options] options << ')' end table = if table.is_a?(::Sequel::Dataset) "(#{table.sql})" else literal(table) end sql = "COPY #{table} TO STDOUT#{options}" end synchronize(opts[:server]) do |conn| conn.execute(sql) begin if block_given? while buf = conn.get_copy_data yield buf end nil else b = '' b << buf while buf = conn.get_copy_data b end ensure raise DatabaseDisconnectError, "disconnecting as a partial COPY may leave the connection in an unusable state" if buf end end end
Execute the given SQL with the given args on an available connection.
# File lib/sequel/adapters/postgres.rb, line 256 def execute(sql, opts={}, &block) check_database_errors do return execute_prepared_statement(sql, opts, &block) if Symbol === sql synchronize(opts[:server]){|conn| conn.execute(sql, opts[:arguments], &block)} end end
Insert the values into the table and return the primary key (if automatically generated).
# File lib/sequel/adapters/postgres.rb, line 265 def execute_insert(sql, opts={}) return execute(sql, opts) if Symbol === sql check_database_errors do synchronize(opts[:server]) do |conn| conn.execute(sql, opts[:arguments]) insert_result(conn, opts[:table], opts[:values]) end end 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).
# File lib/sequel/adapters/postgres.rb, line 359 def listen(channels, opts={}, &block) check_database_errors do synchronize(opts[:server]) do |conn| begin channels = Array(channels) channels.each{|channel| conn.execute("LISTEN #{channel}")} opts[:after_listen].call(conn) if opts[:after_listen] timeout = opts[:timeout] ? [opts[:timeout]] : [] if l = opts[:loop] raise Error, 'calling #listen with :loop requires a block' unless block loop_call = l.respond_to?(:call) catch(:stop) do loop do conn.wait_for_notify(*timeout, &block) l.call(conn) if loop_call end end nil else conn.wait_for_notify(*timeout, &block) end ensure conn.execute("UNLISTEN *") end end end end
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