# File lib/ancestry/class_methods.rb, line 215
      def primary_key_is_an_integer?
        if defined?(@primary_key_is_an_integer)
          @primary_key_is_an_integer
        else
          @primary_key_is_an_integer = !ANCESTRY_UNCAST_TYPES.include?(type_for_attribute(primary_key).type)
        end
      end