    # File lib/active_record/vendor/simple.rb, line 521
        def transaction(action = nil, name = nil)
          case action
          when :start
            start_transaction(name)
          when :rewind
            rewind_transaction(name)
          when :abort
            abort_transaction(name)
          when :commit
            commit_transaction(name)
          when :name
            transaction_name
          when nil
            transaction_open?(name)
          end
        end