python - Flask SQLAlchemy 关联表 : error creating backref

Question

我有一个 Artist 模型和一个 Venue 模型，它们之间存在由 Show 模型促进的多对多关系(演出表明音乐会的艺术家、地点和日期)。

class Venue(db.Model):
__tablename__ = 'Venue'

id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String, unique=True, nullable=False)
shows = db.relationship('Show', backref='venue', lazy=True)   

class Artist(db.Model):
__tablename__ = 'Artist'

id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String, unique=True, nullable=False)
shows = db.relationship('Show', backref='artist', lazy=True)

class Show(db.Model):
  __tablename__ = 'Show'

  id = db.Column(db.Integer, primary_key=True)
  venue_id = db.Column(db.Integer, db.ForeignKey('Venue.id'), nullable=False)
  artist_id = db.Column(db.Integer, db.ForeignKey('Artist.id'), nullable=False)      
  start_time = db.Column(db.DateTime, nullable=False)    
  venue = db.relationship('Venue', back_populates='venue')
  artist = db.relationship('Artist', back_populates='artist')

我想查询所有即将举行的演出的 field 名称、艺术家姓名和日期，因此请记住以下内容...

upcoming_shows = Show.query.filter_by(show.start_time >= datetime.now()).all()

...这样我就可以访问即将到来的节目[0].Venue.name、即将到来的_节目[0].Artist.name 和即将到来的_节目[0].start_time。

但是该查询返回以下内容:

sqlalchemy.exc.ArgumentError: Error creating backref 'venue' on relationship 'Venue.shows': property of that name exists on mapper 'mapped class Show->Show'

感觉我已经很接近了，但缺少一些基本的东西!

Answer 1

已解决。我对代码进行了以下更改，现在它可以工作了。最后相当简单，我只需确保关系名称是唯一的:-\

class Venue(db.Model):
__tablename__ = 'Venue'

id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String, unique=True, nullable=False)
venue_shows = db.relationship('Show', back_populates='venue', lazy=True)   

class Artist(db.Model):
__tablename__ = 'Artist'

id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String, unique=True, nullable=False)
artist_shows = db.relationship('Show', back_populates='artist', lazy=True)

class Show(db.Model):
  __tablename__ = 'Show'

  id = db.Column(db.Integer, primary_key=True)
  venue_id = db.Column(db.Integer, db.ForeignKey('Venue.id'), nullable=False)
  artist_id = db.Column(db.Integer, db.ForeignKey('Artist.id'), nullable=False)    

  start_time = db.Column(db.DateTime, nullable=False)

  venue = db.relationship('Venue', back_populates='venue_shows')
  artist = db.relationship('Artist', back_populates='venue_artist')