小编use*_*914的帖子

I got error message: {DetachedInstanceError} Parent instance is not bound to a session; lazy load operation of attribute 'owner' cannot proceed

My python code:

car_obj = my_query_function()  # get a Car object
owner_name = car_obj.owner.name # here generate error!

My model:

class Person(EntityClass):
    attributes = ['id', 'name']

    name = sa.Column(sa.String(250))


class Car(EntityClass):
    attributes = ['id', 'brand', 'color', 'purchase_time', 'owner_id']

    brand = sa.Column(sa.String(250))
    color = sa.Column(sa.String(250))
    purchase_time = sa.Column(sa.String(250))
    owner_id = sa.Column(DBKeyType, sa.ForeignKey(Person.__tablename__ + '.id'), nullable=False)
    owner = relationship('Person', cascade='all, delete-orphan', …