# File lib/active_record/base.rb, line 553
      def primary_key
        case primary_key_prefix_type
          when :table_name
            Inflector.foreign_key(class_name_of_active_record_descendant(self), false)
          when :table_name_with_underscore
            Inflector.foreign_key(class_name_of_active_record_descendant(self))
          else
            "id"
        end
      end