模型定义：

class Follow(db.Model):    __tablename__ = 'tb_follow'    id = db.Column(db.Integer, primary_key=True)    userid = db.Column(db.Integer, db.ForeignKey('tb_user.id'), nullable=False)    followid = db.Column(db.Integer, db.ForeignKey('tb_user.id'), nullable=False)    createTime = db.Column(db.DateTime, nullable=False, default=datetime.datetime.now)    user = db.relationship('User')    follower = db.relationship('User')    def __init__(self, userid, followid):        self.userid = userid        self.followid = followid    def __repr__(self):        return '
    
     ' % (self.user, self.follower, self.createTime)
    

报错：sqlalchemy.exc.AmbiguousForeignKeysError: Could not determine join condition between parent/child tables on relationship

model中有两个外键引用同一个user表，在db.relationship()时无法确定如何对应。所以，需要借助relationship函数其它参数。如foreign_keys=[xxx]

故模型改为：

class Follow(db.Model):    __tablename__ = 'tb_follow'    id = db.Column(db.Integer, primary_key=True)    userid = db.Column(db.Integer, db.ForeignKey('tb_user.id'), nullable=False)    followid = db.Column(db.Integer, db.ForeignKey('tb_user.id'), nullable=False)    createTime = db.Column(db.DateTime, nullable=False, default=datetime.datetime.now)    user = db.relationship('User', foreign_keys=userid)    follower = db.relationship('User', foreign_keys=followid)    def __init__(self, userid, followid):        self.userid = userid        self.followid = followid    def __repr__(self):        return '
    
     ' % (self.user, self.follower, self.createTime)
    

关键:

user = db.relationship('User', foreign_keys=userid)follower = db.relationship('User', foreign_keys=followid)