Active Record MySQL2 Adapter¶ ↑

# File activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb, line 56
def initialize(...)
  super

  @config[:flags] ||= 0

  if @config[:flags].kind_of? Array
    @config[:flags].push "FOUND_ROWS"
  else
    @config[:flags] |= ::Mysql2::Client::FOUND_ROWS
  end

  @connection_parameters ||= @config
end

# File activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb, line 25
def new_client(config)
  ::Mysql2::Client.new(config)
rescue ::Mysql2::Error => error
  case error.error_number
  when ER_BAD_DB_ERROR
    raise ActiveRecord::NoDatabaseError.db_error(config[:database])
  when ER_DBACCESS_DENIED_ERROR, ER_ACCESS_DENIED_ERROR
    raise ActiveRecord::DatabaseConnectionError.username_error(config[:username])
  when ER_CONN_HOST_ERROR, ER_UNKNOWN_HOST_ERROR
    raise ActiveRecord::DatabaseConnectionError.hostname_error(config[:host])
  else
    raise ActiveRecord::ConnectionNotEstablished, error.message
  end
end

# File activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb, line 70
def active?
  if connected?
    @lock.synchronize do
      if @raw_connection&.ping
        verified!
        true
      end
    end
  end || false
end