use_identity_map

# File activerecord/lib/active_record/inheritance.rb, line 117
      def use_identity_map(sti_class, record_id, record)
        if (column = sti_class.columns_hash[sti_class.primary_key]) && column.number?
          record_id = record_id.to_i
        end

        if instance = IdentityMap.get(sti_class, record_id)
          instance.reinit_with('attributes' => record)
        else
          instance = sti_class.allocate.init_with('attributes' => record)
          IdentityMap.add(instance)
        end

        instance
      end