delete_records

# File activerecord/lib/active_record/associations/has_many_association.rb, line 98
        def delete_records(records, method)
          if method == :destroy
            records.each(&:destroy!)
            update_counter(-records.length) unless reflection.inverse_updates_counter_cache?
          else
            scope = self.scope.where(reflection.klass.primary_key => records)
            update_counter(-delete_count(method, scope))
          end
        end