Python 属性错误：'；功能'；对象没有属性'；地点id'；

我试图做我们网站的用户关注学校功能，我制作了一个关系表（名为“关注”），如下所示

class Follow(db.Model):
    __tablename__ = 'follow'
    follower_id = db.Column(db.Integer, db.ForeignKey('user.id'), primary_key=True)  
    followed_id = db.Column(db.String(50), 
    db.ForeignKey('school.place_id'),primary_key=True)  
    timestamp = db.Column(db.DateTime, default=datetime.utcnow)

用户和学校模型的相关属性为：

 class User(UserMixin, db.Model):
   __tablename__ = 'user'
   id = db.Column(db.Integer, primary_key=True)
   followed = db.relationship('Follow',
                                foreign_keys=[Follow.follower_id],
                                backref=db.backref('follower', lazy='joined'),
                                lazy='dynamic',cascade='all,delete-orphan')
 class School(db.Model):
    _tablename_ = 'school'
    place_id = db.Column(db.String(50), primary_key=True)
    followers = db.relationship('Follow',  
                           foreign_keys=[Follow.followed_id],
                           backref=db.backref('followed,lazy=joined'),  # corresponding followed_id
                           lazy='dynamic',
                           cascade='all, delete-orphan')

此外，我还编写了三种与用户模型中的以下行为相关的方法

def follow(self, school):                          
        if not self.is_following(school):
            f = Follow(follower=self, followed=school)    
            db.session.add(f)                           
            db.session.commit()


def unfollow(self, school):                       
        f = self.followed.filter_by(followed_id=school.place_id).first()       
        if f is not None:
            db.session.delete(f)
            db.session.commit()


def is_following(self,school):
        return self.followed.filter_by(followed_id=school.place_id).first() is not None

我还在main/views.py中写了以下内容

@main.route('/follow/<official_school_name>')
@login_required
# @permission_required(Permission.USER_LIKE)
def follow(official_school_name):
    school = School.query.filter_by(official_school_name=official_school_name).first()
    if school is None:
        flash('Invalid school name.')
        return redirect(url_for('.index'))
    if current_user.is_following(school):
        flash('You have already followed this school.')
        return redirect(url_for('.school', official_school_name=school.official_school_name, roll_number=school.roll_number))
    current_user.follow(user)
    flash('You are not following %s.' % official_school_name)
    return redirect(url_for('.school', official_school_name=school.official_school_name, roll_number=school.roll_number))

我尝试将“is_following”函数更改为：

 def is_following(self,school):
            return self.followed.filter_by(followed_id=school.id).first() is not None

然后出现了另一个错误：

 File "C:\Users\kjhk\venv\lib\site-packages\flask\app.py", line 2309, in __call__
    return self.wsgi_app(environ, start_response)
  File "C:\Users\kjhk\venv\lib\site-packages\werkzeug\contrib\fixers.py", line 152, in __call__
    return self.app(environ, start_response)
  File "C:\Users\kjhk\venv\lib\site-packages\flask\app.py", line 2295, in wsgi_app
    response = self.handle_exception(e)
  File "C:\Users\kjhk\venv\lib\site-packages\flask\app.py", line 1741, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "C:\Users\kjhk\venv\lib\site-packages\flask\_compat.py", line 35, in reraise
    raise value
  File "C:\Users\kjhk\venv\lib\site-packages\flask\app.py", line 2292, in wsgi_app
    response = self.full_dispatch_request()
  File "C:\Users\kjhk\venv\lib\site-packages\flask\app.py", line 1815, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "C:\Users\kjhk\venv\lib\site-packages\flask\app.py", line 1718, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "C:\Users\kjhk\venv\lib\site-packages\flask\_compat.py", line 35, in reraise
    raise value
  File "C:\Users\kjhk\venv\lib\site-packages\flask\app.py", line 1813, in full_dispatch_request
    rv = self.dispatch_request()
  File "C:\Users\kjhk\venv\lib\site-packages\flask\app.py", line 1799, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "C:\Users\kjhk\venv\lib\site-packages\flask_login\utils.py", line 261, in decorated_view
    return func(*args, **kwargs)
  File "E:\Project0619\ProjectTest\Code\app\main\views.py", line 194, in follow
    if current_user.is_following(school):
  File "E:\Project0619\ProjectTest\Code\app\models\User.py", line 113, in is_following
    return self.followed.filter_by(followed_id=school.id).first() is not None
AttributeError: 'School' object has no attribute 'id'

---

这证明了第二个argus（School.id）可以引用“School”模型，但任何人都可以帮助我回答第一个错误出现的原因？非常感谢

此错误：

AttributeError:“School”对象没有属性“id”

不能很好地证明您的其他问题。仔细查看每个调用堆栈可以告诉我们更多关于正在发生的事情：

第一个调用使用

如果不是self.is\u following（school）

作为其入口点，而第二个调用使用

如果当前用户是following（school）

。我可以从你发布的追踪中看到这一点

在第二种情况下，您将学校定义为：

school = School.query.filter_by(official_school_name=official_school_name).first()

在后一种情况下，

school

实际上是

school

类的一个实例

但是，在第一个示例中，学校参数作为

用户

传入：

current_user.follow(user)<-----

当前用户。跟随（用户）
school = School.query.filter_by(official_school_name=official_school_name).first()

current_user.follow(user)<-----