Question

我有两个表User表和Follow表。 User表格有id。 Follow表格有两列Follower和Following，它们是外键，与User表的id相关。

我希望能够轻松地将用户的关注者引用给用户所关注的人，因此我在SQLAlchemy中建立了一个关系，如下所示：

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    ...
    Followers = db.relationship('Follow')
    Following = db.relationship('Follow')

class Follow(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    follower = db.Column(db.Integer, db.ForeignKey('accounts.id', onupdate='CASCADE', ondelete='CASCADE'))
    following = db.Column(db.Integer, db.ForeignKey('accounts.id', onupdate='CASCADE', ondelete='CASCADE'))

我收到了AmbiguousForeignKeysError，说明我应该添加foreign_keys属性，所以我在看到this这样的问题之后就这样做了：

class User(db.Model):
    ...
    Followers = db.relationship('Follow', foreign_keys='follower')
    Following = db.relationship('Follow', foreign_keys='following')

但现在我收到此错误：

InvalidRequestError: When initializing mapper Mapper|User|accounts, expression 'follower' failed to locate a name ("name 'follower' is not defined"). If this is a class name, consider adding this relationship() to the <class 'myapp.views.models.User'> class after both dependent classes have been defined.

问题是什么，我该如何解决？感谢。

SQLAlchemy同一个表的多个外键：InvalidRequestError

0 个答案: