使用flask我碰到的问题

When scattering Flask Models, RuntimeError: ‘application not registered on db’ was raised

有问题代码

app = Flask(__name__)
db.init_app(db)



def test():
    db.create_all()

修改为

def test():
    with app.app_context():
        db.create_all()

Class does not have a table or tablename specified and does not inherit from an existing table-mapped class

Per the Flask-SQLAlchemy docs inheriting from db.Model will automatically setup the table name for you.

The reason you are seeing this message is because you don’t have a primary key defined for that table. The error message is kind of unhelpful, but adding a primary key will fix this problem.

flask-sqlalchemy-多对一， 一对多关系

class Person(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50))
    addresses = db.relationship('Address', backref='person',
                                lazy='dynamic')

class Address(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    email = db.Column(db.String(50))
    person_id = db.Column(db.Integer, db.ForeignKey('person.id'))

当我生成一个 address对象, address 存在一个 persion属性，这个属性名是如何来的？ 答案 persion.id 的 persion来的.

参考

when-scattering-flask-models-runtimeerror-application-not-registered-on-db-w