事發經過 發現建立 cart table 時,漏掉 user_id 這個 foreign key,所以幫 user 和 cart 兩張資料表補上 one-one relationship。 class User(db.Model): __tablename__ = 'user' id = db.Column(db.Integer, primary_key=True) display_name = db.Column(db.String(50), unique=True, nullable=False) email = db.Column(db.String(50), unique=True, nullable=False) password = db.Column(db.String(140), nullable=False) cell_phone = db.Column(db.String(20)) address = db.Column(db.String(100)) store_introduction = db.Column(db.String(2000)) role = db.Column(db.String(10), nullable=False, default='user') insert_time = db.Column(db.DateTime, nullable=False, default=datetime.now) update_time = db.Column(db.DateTime, onupdate=datetime.now, nullable=False, default=datetime.now) cart = db.relationship('Cart', back_populates='user', uselist=False) delivery_orders = db.relationship('Order', back_populates='seller') purchase_order = db.relati...