flask 邻接列表关系(flask 48)

文章的评论有自己的评论，为邻接列表关系

class Comment(db.Model): id = db.Column(db.Integer, primary_key=True) author = db.Column(db.String(30)) email = db.Column(db.String(254)) site = db.Column(db.String(255)) body = db.Column(db.Text) from_admin = db.Column(db.Boolean, default=False) reviewed = db.Column(db.Boolean, default=False) timestamp = db.Column(db.DateTime, default=datetime.utcnow, index=True)

replied_id = db.Column(db.Integer, db.ForeignKey('comment.id'))
post_id = db.Column(db.Integer, db.ForeignKey('post.id'))

post = db.relationship('Post', back_populates='comments')
replies = db.relationship('Comment', back_populates='replied', cascade='all, delete-orphan')
replied = db.relationship('Comment', back_populates='replies', remote_side=[id])