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Question

在我的问题中，假设一个人可以有多个地址，每个地址可以有一个位置。

是否可以查询 Person 包含与其位置相连的地址？

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

class Address(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    email = db.Column(db.String(120), nullable=False)
    person_id = db.Column(db.Integer, db.ForeignKey('person.id'),
        nullable=False)
    location_id = db.Column(db.Integer, ForeignKey('location.id'))

class Location(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    location_name = db.Column(db.String(50), nullable=False)
    address = relationship("Address", uselist=False, backref="location")
    

因此，当我循环人员时，我可以同时从地址和位置访问数据：

for person in persons:
    person.addresses.location_name

Answer 1

类似：

class Person(db.Model):
   def __init__(self):
       self.address = db.session.query( Address).filter( Address.person_id == self.id).first()

   id = db.Column(db.Integer, primary_key=True)
   name = db.Column(db.String(50), nullable=False)
   addresses = db.relationship('Address', backref='person', lazy=True)