Flask-SQLAlchemy: get column in parent table as child model attribute by one-to-many relationship

Question

I have a example about one-to-many relationship in Flask-SQLAlchemy:

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(80))
    email = db.Column(db.String(120), unique=True)
    posts = db.relationship('Post', backref='user')


class Post(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    content = db.Column(db.Text)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id')

According to Declaring Models , I can get list of posts of User U by U.posts . But in constrast, how can I get author's name of Post P as an attribute like P.author_name , instead of P.user.name ?

Answer 1

尝试P.user ，根据您在 backref 中定义的内容

Answer 2

I can modify the Post class by:

class Post(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    content = db.Column(db.Text)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id')

    @cached_property
    def author_name(self):
        return self.user.name

then, it will see P.author_name as P.user.name .