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
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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 } }
 
Class Public 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 environment.rb file:

ActiveRecord::ConnectionAdapters::MysqlAdapter.emulate_booleans = false
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 171
cattr_accessor :emulate_booleans
new(connection, logger, connection_options, config)
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 199
def initialize(connection, logger, connection_options, config)
  super(connection, logger)
  @connection_options, @config = connection_options, config
  @quoted_column_names, @quoted_table_names = {}, {}
  connect
end
Instance Public methods
active?()

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

# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 275
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 = {})
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 485
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)
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 552
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()
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 583
def case_sensitive_equality_operator
  "= BINARY"
end
change_column_null(table_name, column_name, null, default = nil)
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 497
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.

# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 429
def charset
  show_variable 'character_set_database'
end
collation()

Returns the database collation strategy.

# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 434
def collation
  show_variable 'collation_database'
end
create_database(name, options = {})

Create a new MySQL database with optional :charsetand :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
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 412
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()
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 361
def create_savepoint
  execute("SAVEPOINT #{current_savepoint_name}")
end
current_database()
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 424
def current_database
  select_value 'SELECT DATABASE() as db'
end
disconnect!()
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 297
def disconnect!
  @connection.close rescue nil
end
drop_table(table_name, options = {})
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 446
def drop_table(table_name, options = {})
  super(table_name, options)
end
limited_update_conditions(where_sql, quoted_table_name, quoted_primary_key)
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 587
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

# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 578
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 ==================================================

# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 229
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()
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 256
def quoted_false
  QUOTED_FALSE
end
quoted_true()
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 252
def quoted_true
  QUOTED_TRUE
end
reconnect!()
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 292
def reconnect!
  disconnect!
  connect
end
release_savepoint()
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 369
def release_savepoint
  execute("RELEASE SAVEPOINT #{current_savepoint_name}")
end
rename_table(table_name, new_name)
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 481
def rename_table(table_name, new_name)
  execute "RENAME TABLE #{quote_table_name(table_name)} TO #{quote_table_name(new_name)}"
end
reset!()
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 301
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()
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 365
def rollback_to_savepoint
  execute("ROLLBACK TO SAVEPOINT #{current_savepoint_name}")
end
select_rows(sql, name = nil)

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

# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 312
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'

# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 561
def show_variable(name)
  variables = select_all("SHOW VARIABLES LIKE '#{name}'")
  variables.first['Value'] unless variables.empty?
end
type_to_sql(type, limit = nil, precision = nil, scale = nil)

Maps logical Rails types to MySQL-specific data types.

# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 539
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
Instance Protected methods
quoted_columns_for_index(column_names, options = {})
# File activerecord/lib/active_record/connection_adapters/mysql_adapter.rb, line 592
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