小编V. *_*ula的帖子

我想记录一些SQLAlchemy-Models将要完成的操作.

所以,我有一个after_insert,after_delete和before_update钩子,在那里我将保存模型的先前和当前表示,

def keep_logs(cls):
    @event.listens_for(cls, 'after_delete')
    def after_delete_trigger(mapper, connection, target):
        pass

    @event.listens_for(cls, 'after_insert')
    def after_insert_trigger(mapper, connection, target):
        pass

    @event.listens_for(cls, 'before_update')
    def before_update_trigger(mapper, connection, target):
        prev = cls.query.filter_by(id=target.id).one()
        # comparing previous and current model


MODELS_TO_LOGGING = (
    User,
)
for cls in MODELS_TO_LOGGING:
    keep_logs(cls)

但是有一个问题:当我试图在before_update钩子中找到模型时,SQLA返回修改(脏)版本.如何在更新之前获取以前版本的模型？是否有不同的方法来保持模型更改？

谢谢!