Class: Sequel::Postgres::Database

Inherits:
Database show all
Includes:
DatabaseMethods
Defined in:
lib/sequel/adapters/postgres.rb

Overview

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

Constant Summary collapse

DatasetClass = 
self

Constants included from DatabaseMethods

Sequel::Postgres::DatabaseMethods::EXCLUDE_SCHEMAS, Sequel::Postgres::DatabaseMethods::PREPARED_ARG_PLACEHOLDER, Sequel::Postgres::DatabaseMethods::RE_CURRVAL_ERROR, Sequel::Postgres::DatabaseMethods::SYSTEM_TABLE_REGEXP

Constants inherited from Database

Database::ADAPTERS, Database::AUTOINCREMENT, Database::CASCADE, Database::COLUMN_DEFINITION_ORDER, Database::COMMA_SEPARATOR, Database::MSSQL_DEFAULT_RE, Database::MYSQL_TIMESTAMP_RE, Database::NOT_NULL, Database::NO_ACTION, Database::NULL, Database::POSTGRES_DEFAULT_RE, Database::PRIMARY_KEY, Database::RESTRICT, Database::SET_DEFAULT, Database::SET_NULL, Database::SQL_BEGIN, Database::SQL_COMMIT, Database::SQL_RELEASE_SAVEPOINT, Database::SQL_ROLLBACK, Database::SQL_ROLLBACK_TO_SAVEPOINT, Database::SQL_SAVEPOINT, Database::STRING_DEFAULT_RE, Database::TEMPORARY, Database::TRANSACTION_BEGIN, Database::TRANSACTION_COMMIT, Database::TRANSACTION_ISOLATION_LEVELS, Database::TRANSACTION_ROLLBACK, Database::UNDERSCORE, Database::UNIQUE, Database::UNSIGNED

Instance Attribute Summary collapse

Attributes inherited from Database

#dataset_class, #default_schema, #log_warn_duration, #loggers, #opts, #pool, #prepared_statements, #sql_log_level, #timezone, #transaction_isolation_level

Instance Method Summary collapse

Methods included from DatabaseMethods

#commit_prepared_transaction, #create_function, #create_language, #create_trigger, #database_type, #drop_function, #drop_language, #drop_trigger, #indexes, #locks, #notify, #primary_key, #primary_key_sequence, #reset_primary_key_sequence, #rollback_prepared_transaction, #serial_primary_key_options, #server_version, #supports_create_table_if_not_exists?, #supports_prepared_transactions?, #supports_savepoints?, #supports_transaction_isolation_levels?, #tables, #views

Methods inherited from Database

#<<, #[], adapter_class, #adapter_scheme, adapter_scheme, #add_column, #add_index, #add_servers, #after_commit, #after_rollback, #alter_table, #call, #cast_type_literal, connect, #create_or_replace_view, #create_table, #create_table!, #create_table?, #create_view, #database_type, #dataset, #disconnect, #drop_column, #drop_index, #drop_table, #drop_view, #dump_indexes_migration, #dump_schema_migration, #dump_table_schema, #each_server, #execute_ddl, #execute_dui, #extend_datasets, #fetch, #from, #from_application_timestamp, #get, #identifier_input_method, identifier_input_method, identifier_input_method=, #identifier_input_method=, #identifier_output_method, identifier_output_method, identifier_output_method=, #identifier_output_method=, #in_transaction?, #indexes, #inspect, #literal, #log_info, #log_yield, #logger=, #query, #quote_identifiers=, quote_identifiers=, #quote_identifiers?, #remove_servers, #rename_column, #rename_table, #run, #schema, #select, #serial_primary_key_options, #servers, #set_column_default, #set_column_type, single_threaded=, #single_threaded?, #supports_create_table_if_not_exists?, #supports_prepared_transactions?, #supports_savepoints?, #supports_transaction_isolation_levels?, #synchronize, #table_exists?, #tables, #test_connection, #to_application_timestamp, #transaction, #typecast_value, #uri, #url, #views

Methods included from Metaprogramming

#meta_def

Constructor Details

#initialize(*args) ⇒ Database

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



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# File 'lib/sequel/adapters/postgres.rb', line 210

def initialize(*args)
  super
  @primary_keys = {}
  @primary_key_sequences = {}
end

Instance Attribute Details

#conversion_procs ⇒ Object (readonly)

A hash of conversion procs, keyed by type integer (oid) and having callable values for the conversion proc for that type.



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# File 'lib/sequel/adapters/postgres.rb', line 206

def conversion_procs
  @conversion_procs
end

Instance Method Details

#connect(server) ⇒ Object

Connects to the database. In addition to the standard database options, using the :encoding or :charset option changes the client encoding for the connection.



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# File 'lib/sequel/adapters/postgres.rb', line 219

def connect(server)
  opts = server_opts(server)
  conn = Adapter.connect(
    (opts[:host] unless blank_object?(opts[:host])),
    opts[:port] || 5432,
    nil, '',
    opts[:database],
    opts[:user],
    opts[:password]
  )
  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(table, opts = {}) ⇒ Object

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.



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# File 'lib/sequel/adapters/postgres.rb', line 289

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(sql, opts = {}, &block) ⇒ Object

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



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# File 'lib/sequel/adapters/postgres.rb', line 243

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

#execute_insert(sql, opts = {}) ⇒ Object

Insert the values into the table and return the primary key (if automatically generated).



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# File 'lib/sequel/adapters/postgres.rb', line 252

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

#listen(channels, opts = {}, &block) ⇒ Object

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).



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# File 'lib/sequel/adapters/postgres.rb', line 346

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