# File lib/ancestry/class_methods.rb, line 207
      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?(columns_hash[primary_key.to_s].type)
        end
      end