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).

  • :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.

Methods
Constants
ADAPTER_NAME = 'MySQL'.freeze
LOST_CONNECTION_ERROR_MESSAGES = [ "Server shutdown in progress", "Broken pipe", "Lost connection to MySQL server during query", "MySQL server has gone away" ]
QUOTED_FALSE = '1'.freeze, '0'.freeze
NATIVE_DATABASE_TYPES = { :primary_key => "int(11) DEFAULT NULL auto_increment PRIMARY KEY".freeze, :string => { :name => "varchar", :limit => 255 }, :text => { :name => "text" }, :integer => { :name => "int", :limit => 4 }, :float => { :name => "float" }, :decimal => { :name => "decimal" }, :datetime => { :name => "datetime" }, :timestamp => { :name => "datetime" }, :time => { :name => "time" }, :date => { :name => "date" }, :binary => { :name => "blob" }, :boolean => { :name => "tinyint", :limit => 1 } }
Public Class methods
emulate_booleans

By default, the MysqlAdapter will consider all columns of type tinyint(1) as boolean. If you wish to disable this emulation (which was the default behavior in versions 0.13.1 and earlier) you can add the following line to your application.rb file:

ActiveRecord::ConnectionAdapters::MysqlAdapter.emulate_booleans = false

[ show source ]

  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 132
cattr_accessor :emulate_booleans
new(connection, logger, connection_options, config)

[ show source ]

  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 160
def initialize(connection, logger, connection_options, config)
  super(connection, logger)
  @connection_options, @config = connection_options, config
  @quoted_column_names, @quoted_table_names = {}, {}
  connect
end
Public Instance methods
active?()

CONNECTION MANAGEMENT ====================================

[ show source ]

  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 236
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
add_column(table_name, column_name, type, options = {})

[ show source ]

  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 466
def add_column(table_name, column_name, type, options = {})
  add_column_sql = "ALTER TABLE #{quote_table_name(table_name)} ADD #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
  add_column_options!(add_column_sql, options)
  add_column_position!(add_column_sql, options)
  execute(add_column_sql)
end
add_column_position!(sql, options)

[ show source ]

  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 533
def add_column_position!(sql, options)
  if options[:first]
    sql << " FIRST"
  elsif options[:after]
    sql << " AFTER #{quote_column_name(options[:after])}"
  end
end
case_sensitive_equality_operator()

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  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 564
def case_sensitive_equality_operator
  "= BINARY"
end
change_column_null(table_name, column_name, null, default = nil)

[ show source ]

  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 478
def change_column_null(table_name, column_name, null, default = nil)
  column = column_for(table_name, column_name)

  unless null || default.nil?
    execute("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote(default)} WHERE #{quote_column_name(column_name)} IS NULL")
  end

  change_column table_name, column_name, column.sql_type, :null => null
end
charset()

Returns the database character set.

[ show source ]

  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 396
def charset
  show_variable 'character_set_database'
end
collation()

Returns the database collation strategy.

[ show source ]

  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 401
def collation
  show_variable 'collation_database'
end
create_database(name, options = {})

Create a new MySQL database with optional :charset and :collation. Charset defaults to utf8.

Example:

create_database 'charset_test', :charset => 'latin1', :collation => 'latin1_bin'
create_database 'matt_development'
create_database 'matt_development', :charset => :big5

[ show source ]

  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 379
def create_database(name, options = {})
  if options[:collation]
    execute "CREATE DATABASE `#{name}` DEFAULT CHARACTER SET `#{options[:charset] || 'utf8'}` COLLATE `#{options[:collation]}`"
  else
    execute "CREATE DATABASE `#{name}` DEFAULT CHARACTER SET `#{options[:charset] || 'utf8'}`"
  end
end
create_savepoint()

[ show source ]

  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 328
def create_savepoint
  execute("SAVEPOINT #{current_savepoint_name}")
end
current_database()

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  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 391
def current_database
  select_value 'SELECT DATABASE() as db'
end
disconnect!()

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  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 258
def disconnect!
  @connection.close rescue nil
end
drop_table(table_name, options = {})

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  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 427
def drop_table(table_name, options = {})
  super(table_name, options)
end
limited_update_conditions(where_sql, quoted_table_name, quoted_primary_key)

[ show source ]

  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 568
def limited_update_conditions(where_sql, quoted_table_name, quoted_primary_key)
  where_sql
end
primary_key(table)

Returns just a table’s primary key

[ show source ]

  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 559
def primary_key(table)
  pk_and_sequence = pk_and_sequence_for(table)
  pk_and_sequence && pk_and_sequence.first
end
quote(value, column = nil)

QUOTING ==================================================

[ show source ]

  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 190
def quote(value, column = nil)
  if value.kind_of?(String) && column && column.type == :binary && column.class.respond_to?(:string_to_binary)
    s = column.class.string_to_binary(value).unpack("H*")[0]
    "x'#{s}'"
  elsif value.kind_of?(BigDecimal)
    value.to_s("F")
  else
    super
  end
end
quoted_false()

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  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 217
def quoted_false
  QUOTED_FALSE
end
quoted_true()

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  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 213
def quoted_true
  QUOTED_TRUE
end
reconnect!()

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  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 253
def reconnect!
  disconnect!
  connect
end
release_savepoint()

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  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 336
def release_savepoint
  execute("RELEASE SAVEPOINT #{current_savepoint_name}")
end
rename_table(table_name, new_name)

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  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 462
def rename_table(table_name, new_name)
  execute "RENAME TABLE #{quote_table_name(table_name)} TO #{quote_table_name(new_name)}"
end
reset!()

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  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 262
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
rollback_to_savepoint()

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  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 332
def rollback_to_savepoint
  execute("ROLLBACK TO SAVEPOINT #{current_savepoint_name}")
end
select_rows(sql, name = nil)

DATABASE STATEMENTS ======================================

[ show source ]

  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 273
def select_rows(sql, name = nil)
  @connection.query_with_result = true
  result = execute(sql, name)
  rows = []
  result.each { |row| rows << row }
  result.free
  @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
show_variable(name)

SHOW VARIABLES LIKE ‘name’

[ show source ]

  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 542
def show_variable(name)
  variables = select_all("SHOW VARIABLES LIKE '#{name}'")
  variables.first['Value'] unless variables.empty?
end
table_exists?(name)

[ show source ]

  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 413
def table_exists?(name)
  return true if super

  name          = name.to_s
  schema, table = name.split('.', 2)

  unless table # A table was provided without a schema
    table  = schema
    schema = nil
  end

  tables(nil, schema).include? table
end
type_to_sql(type, limit = nil, precision = nil, scale = nil)

Maps logical Rails types to MySQL-specific data types.

[ show source ]

  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 520
def type_to_sql(type, limit = nil, precision = nil, scale = nil)
  return super unless type.to_s == 'integer'

  case limit
  when 1; 'tinyint'
  when 2; 'smallint'
  when 3; 'mediumint'
  when nil, 4, 11; 'int(11)'  # compatibility with MySQL default
  when 5..8; 'bigint'
  else raise(ActiveRecordError, "No integer type has byte size #{limit}")
  end
end
Protected Instance methods
quoted_columns_for_index(column_names, options = {})

[ show source ]

  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 573
def quoted_columns_for_index(column_names, options = {})
  length = options[:length] if options.is_a?(Hash)

  quoted_column_names = case length
  when Hash
    column_names.map {|name| length[name] ? "#{quote_column_name(name)}(#{length[name]})" : quote_column_name(name) }
  when Fixnum
    column_names.map {|name| "#{quote_column_name(name)}(#{length})"}
  else
    column_names.map {|name| quote_column_name(name) }
  end
end
translate_exception(exception, message)

[ show source ]

  # File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 586
def translate_exception(exception, message)
  return super unless exception.respond_to?(:errno)

  case exception.errno
  when 1062
    RecordNotUnique.new(message, exception)
  when 1452
    InvalidForeignKey.new(message, exception)
  else
    super
  end
end