persistence.py 文件源码

def _validate_query_state(self):
        for attr, methname, notset, op in (
            ('_limit', 'limit()', None, operator.is_),
            ('_offset', 'offset()', None, operator.is_),
            ('_order_by', 'order_by()', False, operator.is_),
            ('_group_by', 'group_by()', False, operator.is_),
            ('_distinct', 'distinct()', False, operator.is_),
            (
                '_from_obj',
                'join(), outerjoin(), select_from(), or from_self()',
                (), operator.eq)
        ):
            if not op(getattr(self.query, attr), notset):
                raise sa_exc.InvalidRequestError(
                    "Can't call Query.update() or Query.delete() "
                    "when %s has been called" %
                    (methname, )
                )