因此,作為個人項目,我正在開發一個小型博客風格的 Web 應用程序。我現在已經基本可以正常工作了,但是我在嘗試對帖子發表評論時遇到了麻煩。我設置帖子的方式是通過 SQLAlchemy ORM 模型,效果很好。它有內容和標題字段等等,以及與帖子作者的多對一關系,如下所示:class Post(db.Model): id = db.Column(db.Integer, primary_key = True) title = db.Column(db.String(100), nullable=False) date_posted = db.Column(db.DateTime, nullable=False, default=datetime.utcnow) content = db.Column(db.Text, nullable=False) feature_image = db.Column(db.String, nullable=True) user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False) comments = db.relationship('Comment', backref='original_post', lazy=True)我的評論遵循相同的結構,與帖子具有多對一的關系,如下所示:class Comment(db.Model): id = db.Column(db.Integer, primary_key = True) date_posted = db.Column(db.DateTime, nullable=False, default=datetime.utcnow) content = db.Column(db.Text, nullable=False) post_id = db.Column(db.Integer, db.ForeignKey('post.id'), nullable=False) user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)因此,為了讓評論顯示在帖子下方,我試圖查詢“評論”表并從“帖子”表中過濾“post_id”,它應該與 post.id 相匹配:@app.route('/post/<int:post_id>')def post(post_id): post = Post.query.get_or_404(post_id) comments = Comment.query.filter(Comment.original_post==post)但是當我嘗試加載帖子頁面時,它會拋出以下錯誤:sqlalchemy.exc.OperationalError: (sqlite3.OperationalError) no such column: comment.post_id[SQL: SELECT comment.id AS comment_id, comment.date_posted AS comment_date_posted, comment.content AS comment_content, comment.post_id AS comment_post_id, comment.user_id AS comment_user_id FROM comment WHERE ? = comment.post_id][parameters: (1,)](Background on this error at: http://sqlalche.me/e/e3q8)我查看了有關該主題的其他一些主題,建議在查詢之前使用 .join ,如下所示:comments = Comment.query.join(Post).filter(Post.id == post_id).all()
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