小编Kra*_*ang的帖子

我有两个映射对象，父对象和子对象。

class Parent(Base):
    __tablename__ = 'parent'
    id = ...
    name = ...
    date_modified = Column(SA_DateTime, default=DateTime.now,
                           onupdate=DateTime.now, nullable=False)

class Child(Base):
    __tablename__ = 'child'
    id = ...
    name = ...
    date_modified = Column(SA_DateTime, default=DateTime.now,
                           onupdate=DateTime.now, nullable=False)
    parent = relationship(Parent, backref='parent')

当孩子更新时，我不仅Child.date_modified要更改，还要更改Child.parent.date_modified.

我试图这样做：

@event.listens_for(Child, 'after_update')
def modified_listener(mapper, connection, target):
    if object_session(target).is_modified(target, include_collections=False):
        target.parent.date_modified = DateTime.now()

但这不起作用，因为我已经处于冲洗状态并且我得到了类似的东西

SAWarning: Attribute history events accumulated on 1 previously clean instance within inner-flush event handlers have been reset, and will not result in …