flask - 加入的表丢失了 'id' 属性

Question

我正在尝试加入两个表，以便能够将相应的“主题”与“主题”相关联。连接似乎有效，但模板在渲染时出现此错误:

jinja2.exceptions.UndefinedError: 'sqlalchemy.util._collections.result object' has no attribute 'id'

加入表格后如何处理 Topic.id？

楷模

class Topic(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    topic_name = db.Column(db.String(64))
    opinions = db.relationship(Opinion, backref='topic')
    theme_id = db.Column(db.Integer, db.ForeignKey('theme.id'))

class Theme(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    theme_name = db.Column(db.String(64))
    topics = db.relationship(Topic, backref='theme')

看法

@main.route('/topics', methods=['GET', 'POST'])
def topics():
    topics = db.session.query(Topic, Theme).join(Theme).order_by(Theme.theme_name).all()
    themes = Theme.query
    form = TopicForm()
    form.theme.choices = [(t.id, t.theme_name) for t in Theme.query.order_by('theme_name')]
    if form.validate_on_submit():
        topic = Topic(topic_name=form.topic_name.data,
                    theme_id=form.theme.data)
        db.session.add(topic)
    return render_template('topics.html', topics=topics, themes=themes, form=form)

html jinja2 模板

<table class="table table-hover parties">
        <thead><tr><th>Theme</th><th>#</th><th>Name</th><th>Delete</th></tr></thead>
        {% for topic in topics %}
        <tr>
            <td><a href="#">{{ topic.theme_id }}</a></td>
            <td><a href="#">{{ topic.id }}</a></td>
            <td><a href="#">{{ topic.topic_name }}<span class="badge">0</span></a></td>
            <td><a class="btn btn-danger btn-xs" href="{{ url_for('main.delete_topic', id=topic.id) }}" role="button">Delete</a></td>
        </tr>
        {% endfor %}
    </table>

Answer 1

将您的查询更改为:

topics = db.session.query(Topic).join(Theme).order_by(Theme.theme_name).all()

使用 query(Topic)表示我们有兴趣获取 Topic值回来。相比之下，您当前的实现使用 query(Topic, Theme)这表明您有兴趣获取 (Topic, Theme) 的元组.