class ActiveRecord::ConnectionAdapters::MysqlAdapter - activerecord-4.2.3 Documentation

# class ActiveRecord::ConnectionAdapters::MysqlAdapter

The MySQL adapter will work with both Ruby/MySQL, which is a Ruby-based MySQL adapter that comes bundled with Active Record, and with the faster C-based MySQL/Ruby adapter (available both as a gem and from www.tmtm.org/en/mysql/ruby/).

Options:

- `:host` - Defaults to “localhost”.

- `:port` - Defaults to 3306.

- `:socket` - Defaults to “/tmp/mysql.sock”.

- `:username` - Defaults to “root”

- `:password` - Defaults to nothing.

- `:database` - The name of the database. No default, must be provided.

- `:encoding` - (Optional) Sets the client encoding by executing “SET NAMES <encoding>” after connection.

- `:reconnect` - Defaults to false (See MySQL documentation: dev.mysql.com/doc/refman/5.0/en/auto-reconnect.html).

- `:strict` - Defaults to true. Enable STRICT_ALL_TABLES. (See MySQL documentation: dev.mysql.com/doc/refman/5.0/en/sql-mode.html)

- `:variables` - (Optional) A hash session variables to send as `SET @@SESSION.key = value` on each database connection. Use the value `:default` to set a variable to its DEFAULT value. (See MySQL documentation: dev.mysql.com/doc/refman/5.0/en/set-statement.html).

- `:sslca` - Necessary to use MySQL with an SSL connection.

- `:sslkey` - Necessary to use MySQL with an SSL connection.

- `:sslcert` - Necessary to use MySQL with an SSL connection.

- `:sslcapath` - Necessary to use MySQL with an SSL connection.

- `:sslcipher` - Necessary to use MySQL with an SSL connection.

### Constants

ADAPTER_NAME
ENCODINGS

  Taken from here:

      https://github.com/tmtm/ruby-mysql/blob/master/lib/mysql/charset.rb

  Author: TOMITA Masahiro <tommy@tmtm.org>

### Public Class Methods

new(connection, logger, connection_options, config) click to toggle source
Calls superclass method ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter.new

    # File lib/active_record/connection_adapters/mysql_adapter.rb, line 103
    def initialize(connection, logger, connection_options, config)
      super
      @statements = StatementPool.new(@connection,
                                      self.class.type_cast_config_to_integer(config.fetch(:statement_limit) { 1000 }))
      @client_encoding = nil
      connect
    end

### Public Instance Methods

active?() click to toggle source

    # File lib/active_record/connection_adapters/mysql_adapter.rb, line 144
    def active?
      if @connection.respond_to?(:stat)
        @connection.stat
      else
        @connection.query 'select 1'
      end

      # mysql-ruby doesn't raise an exception when stat fails.
      if @connection.respond_to?(:errno)
        @connection.errno.zero?
      else
        true
      end
    rescue Mysql::Error
      false
    end

clear_cache!() click to toggle source

Clears the prepared statements cache.

Calls superclass method ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter#clear_cache!

    # File lib/active_record/connection_adapters/mysql_adapter.rb, line 195
    def clear_cache!
      super
      @statements.clear
    end

client_encoding() click to toggle source

Get the client encoding for this database

    # File lib/active_record/connection_adapters/mysql_adapter.rb, line 244
    def client_encoding
      return @client_encoding if @client_encoding

      result = exec_query(
        "SHOW VARIABLES WHERE Variable_name = 'character_set_client'",
        'SCHEMA')
      @client_encoding = ENCODINGS[result.rows.last.last]
    end

disconnect!() click to toggle source

Disconnects from the database if already connected. Otherwise, this method does nothing.

Calls superclass method ActiveRecord::ConnectionAdapters::AbstractAdapter#disconnect!

    # File lib/active_record/connection_adapters/mysql_adapter.rb, line 169
    def disconnect!
      super
      @connection.close rescue nil
    end

exec_query(sql, name = 'SQL', binds = []) { |affected_rows| ... } click to toggle source

    # File lib/active_record/connection_adapters/mysql_adapter.rb, line 253
    def exec_query(sql, name = 'SQL', binds = [])
      if without_prepared_statement?(binds)
        result_set, affected_rows = exec_without_stmt(sql, name)
      else
        result_set, affected_rows = exec_stmt(sql, name, binds)
      end

      yield affected_rows if block_given?

      result_set
    end

last_inserted_id(result) click to toggle source

    # File lib/active_record/connection_adapters/mysql_adapter.rb, line 265
    def last_inserted_id(result)
      @connection.insert_id
    end

reconnect!() click to toggle source
Calls superclass method ActiveRecord::ConnectionAdapters::AbstractAdapter#reconnect!

    # File lib/active_record/connection_adapters/mysql_adapter.rb, line 161
    def reconnect!
      super
      disconnect!
      connect
    end

reset!() click to toggle source

    # File lib/active_record/connection_adapters/mysql_adapter.rb, line 174
    def reset!
      if @connection.respond_to?(:change_user)
        # See http://bugs.mysql.com/bug.php?id=33540 -- the workaround way to
        # reset the connection is to change the user to the same user.
        @connection.change_user(@config[:username], @config[:password], @config[:database])
        configure_connection
      end
    end

select_rows(sql, name = nil, binds = []) click to toggle source

    # File lib/active_record/connection_adapters/mysql_adapter.rb, line 187
    def select_rows(sql, name = nil, binds = [])
      @connection.query_with_result = true
      rows = exec_query(sql, name, binds).rows
      @connection.more_results && @connection.next_result    # invoking stored procedures with CLIENT_MULTI_RESULTS requires this to tidy up else connection will be dropped
      rows
    end

supports_statement_cache?() click to toggle source

Returns true, since this connection adapter supports prepared statement caching.

    # File lib/active_record/connection_adapters/mysql_adapter.rb, line 113
    def supports_statement_cache?
      true
    end

### Private Instance Methods

configure_connection() click to toggle source

Many Rails applications monkey-patch a replacement of the #configure_connection method and don't call 'super', so leave this here even though it looks superfluous.

Calls superclass method ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter#configure_connection

    # File lib/active_record/connection_adapters/mysql_adapter.rb, line 466
    def configure_connection
      super
    end

connect() click to toggle source

    # File lib/active_record/connection_adapters/mysql_adapter.rb, line 442
    def connect
      encoding = @config[:encoding]
      if encoding
        @connection.options(Mysql::SET_CHARSET_NAME, encoding) rescue nil
      end

      if @config[:sslca] || @config[:sslkey]
        @connection.ssl_set(@config[:sslkey], @config[:sslcert], @config[:sslca], @config[:sslcapath], @config[:sslcipher])
      end

      @connection.options(Mysql::OPT_CONNECT_TIMEOUT, @config[:connect_timeout]) if @config[:connect_timeout]
      @connection.options(Mysql::OPT_READ_TIMEOUT, @config[:read_timeout]) if @config[:read_timeout]
      @connection.options(Mysql::OPT_WRITE_TIMEOUT, @config[:write_timeout]) if @config[:write_timeout]

      @connection.real_connect(*@connection_options)

      # reconnect must be set after real_connect is called, because real_connect sets it to false internally
      @connection.reconnect = !!@config[:reconnect] if @connection.respond_to?(:reconnect=)

      configure_connection
    end

exec_stmt(sql, name, binds) click to toggle source

    # File lib/active_record/connection_adapters/mysql_adapter.rb, line 396
    def exec_stmt(sql, name, binds)
      cache = {}
      type_casted_binds = binds.map { |col, val|
        [col, type_cast(val, col)]
      }

      log(sql, name, type_casted_binds) do
        if binds.empty?
          stmt = @connection.prepare(sql)
        else
          cache = @statements[sql] ||= {
            :stmt => @connection.prepare(sql)
          }
          stmt = cache[:stmt]
        end

        begin
          stmt.execute(*type_casted_binds.map { |_, val| val })
        rescue Mysql::Error => e
          # Older versions of MySQL leave the prepared statement in a bad
          # place when an error occurs. To support older MySQL versions, we
          # need to close the statement and delete the statement from the
          # cache.
          stmt.close
          @statements.delete sql
          raise e
        end

        cols = nil
        if metadata = stmt.result_metadata
          cols = cache[:cols] ||= metadata.fetch_fields.map { |field|
            field.name
          }
          metadata.free
        end

        result_set = ActiveRecord::Result.new(cols, stmt.to_a) if cols
        affected_rows = stmt.affected_rows

        stmt.free_result
        stmt.close if binds.empty?

        [result_set, affected_rows]
      end
    end

full_version() click to toggle source

Returns the full version of the connected MySQL server.

    # File lib/active_record/connection_adapters/mysql_adapter.rb, line 478
    def full_version
      @full_version ||= @connection.server_info
    end

select(sql, name = nil, binds = []) click to toggle source
Calls superclass method

    # File lib/active_record/connection_adapters/mysql_adapter.rb, line 470
    def select(sql, name = nil, binds = [])
      @connection.query_with_result = true
      rows = super
      @connection.more_results && @connection.next_result    # invoking stored procedures with CLIENT_MULTI_RESULTS requires this to tidy up else connection will be dropped
      rows
    end

set_field_encoding(field_name) click to toggle source

    # File lib/active_record/connection_adapters/mysql_adapter.rb, line 482
    def set_field_encoding field_name
      field_name.force_encoding(client_encoding)
      if internal_enc = Encoding.default_internal
        field_name = field_name.encode!(internal_enc)
      end
      field_name
    end