Question

我尝试使用Flask和SQLAlchemy建立一个API。

此处的示例：https://github.com/miguelgrinberg/REST-auth/blob/master/api.py

现在这些是我的两个班级：

class User(db.Model):
    __tablename__ = 'users'
    id = db.Column(db.Integer, primary_key=True)
    email = db.Column(db.String(255), index=True) #, unique=True)
    firstname = db.Column(db.String(50))
    lastname = db.Column(db.String(50))
    password_hash = db.Column(db.String(64))

    bt_ids = db.relationship("BT", order_by="BT.id", backref="user")

    def hash_password(self, password):
        self.password_hash = pwd_context.encrypt(password)

    def verify_password(self, password):
        return pwd_context.verify(password, self.password_hash)

    def generate_auth_token(self, expiration=600):
        s = Serializer(app.config['SECRET_KEY'], expires_in=expiration)
        return s.dumps({'id': self.id})

    @staticmethod
    def verify_auth_token(token):
        s = Serializer(app.config['SECRET_KEY'])
        try:
            data = s.loads(token)
        except SignatureExpired:
            return None # valid token, but expired
        except BadSignature:
            return None # invalid token
        user = User.query.get(data['id'])
        return user

class BT(db.Model):
    __tablename__ = 'bt'
    id = db.Column(db.Integer, primary_key=True)
    bt_id = db.Column(db.String(255), unique=True)
    user_id = db.Column(db.Integer, db.ForeignKey('users.id'))

    user = db.relationship("User", backref=db.backref('bt_ids', order_by=id))

但是当我做这样的事情来查询它时：

qemail = User.query.filter_by（email =＆＃39; test@test.com'）。first（）

我收到 500内部服务器错误

当我打开Flask_Debug时，这是信息：

sqlalchemy.exc.ArgumentError



ArgumentError: Error creating backref 'user' on relationship 'User.bt_ids': property of that name exists on mapper 'Mapper|BT|bt'



Traceback (most recent call last)



File "C:\Python27\lib\site-packages\flask\app.py", line 1836, in __call__



return self.wsgi_app(environ, start_response)

File "C:\Python27\lib\site-packages\flask\app.py", line 1820, in wsgi_app



response = self.make_response(self.handle_exception(e))

File "C:\Python27\lib\site-packages\flask\app.py", line 1403, in handle_exception



reraise(exc_type, exc_value, tb)

File "C:\Python27\lib\site-packages\flask\app.py", line 1817, in wsgi_app



response = self.full_dispatch_request()

File "C:\Python27\lib\site-packages\flask\app.py", line 1477, in full_dispatch_request



rv = self.handle_user_exception(e)

File "C:\Python27\lib\site-packages\flask\app.py", line 1381, in handle_user_exception



reraise(exc_type, exc_value, tb)

File "C:\Python27\lib\site-packages\flask\app.py", line 1475, in full_dispatch_request



rv = self.dispatch_request()

File "C:\Python27\lib\site-packages\flask\app.py", line 1461, in dispatch_request



return self.view_functions[rule.endpoint](**req.view_args)

File "C:\Users\kwmaster\Documents\Forx\RestAPI2", line 97, in new_user



email7 = User.query.filter_by(email='kai.wieland@gmail.com').first()

File "C:\Python27\lib\site-packages\flask_sqlalchemy\__init__.py", line 452, in __get__



mapper = orm.class_mapper(type)

File "C:\Python27\lib\site-packages\sqlalchemy\orm\base.py", line 412, in class_mapper



mapper = _inspect_mapped_class(class_, configure=configure)

File "C:\Python27\lib\site-packages\sqlalchemy\orm\base.py", line 391, in _inspect_mapped_class



mapper._configure_all()

File "C:\Python27\lib\site-packages\sqlalchemy\orm\mapper.py", line 1156, in _configure_all



configure_mappers()

File "C:\Python27\lib\site-packages\sqlalchemy\orm\mapper.py", line 2589, in configure_mappers



mapper._post_configure_properties()

File "C:\Python27\lib\site-packages\sqlalchemy\orm\mapper.py", line 1694, in _post_configure_properties



prop.init()

File "C:\Python27\lib\site-packages\sqlalchemy\orm\interfaces.py", line 144, in init



self.do_init()

File "C:\Python27\lib\site-packages\sqlalchemy\orm\relationships.py", line 1553, in do_init



self._generate_backref()

File "C:\Python27\lib\site-packages\sqlalchemy\orm\relationships.py", line 1743, in _generate_backref



(backref_key, self, m))

ArgumentError: Error creating backref 'user' on relationship 'User.bt_ids': property of that name exists on mapper 'Mapper|BT|bt'

Answer 1

您的user模型中已经有一个名为BT的属性，并且您正在尝试通过backref创建另一个属性。你应该删除

行

bt_ids = db.relationship("BT", order_by="BT.id", backref="user")

或将backref名称更改为唯一。

带烧瓶查询的SQLAlchemy不起作用（内部服务器错误500）

1 个答案: