Question

我想显示博客文章的类别（多对多关系）。如何使用SQL-Alchemy正确查询它们，并在HTML模板中使用Jinja2显示它们？

models.py

category_post = db.Table('category_post',
                         db.Column('posts_id', db.Integer, db.ForeignKey('posts.id')),
                         db.Column('categories_id', db.Integer, db.ForeignKey('categories.id'))
)


class Post(db.Model):
    __tablename__ = 'posts'
    id = db.Column(db.Integer, primary_key=True)
    timestamp = db.Column(db.DateTime, index=True, default=datetime.utcnow)
    author_id = db.Column(db.Integer, db.ForeignKey('users.id'))
    active = db.Column(db.Boolean, default="0")
    categories = db.relationship('Category',
                                 secondary=category_post,
                                 backref=db.backref('posts', lazy='dynamic'),
                                 lazy='dynamic')
    comments = db.relationship('Comment', backref='post', lazy='dynamic')
    en_title = db.Column(db.String(128))
    de_title = db.Column(db.String(128))
    en_subtitle = db.Column(db.String(128))
    de_subtitle = db.Column(db.String(128))
    en_description = db.Column(db.String(256))
    de_description = db.Column(db.String(256))
    en_body = db.Column(db.Text)
    de_body = db.Column(db.Text)
    en_url = db.Column(db.String(128))
    de_url = db.Column(db.String(128))


class Category(db.Model):
    __tablename__ = 'categories'
    id = db.Column(db.Integer, primary_key=True)
    en_name = db.Column(db.String(128))
    en_url = db.Column(db.String(128))
    de_name = db.Column(db.String(128))
    de_url = db.Column(db.String(128))

views.py

@main.route('/')
def index():
    posts = Post.query.filter_by(active="1").order_by(Post.timestamp.desc())
    return render_template('index.html', posts=posts)

模板

<div class="ui items">
            {% for post in posts %}
            <div class="item">
                <div class="image">
                    <div class="ui placeholder">
                        <div class="square image"></div>
                    </div>
                </div>
                <div class="middle aligned content">
                    <a class="header" href="{{ _(post.en_url) }}">{{ _(post.en_title) }}</a>
                    <div class="meta">
                        <span>{{ _(post.en_subtitle) }}</span>
                    </div>
                    <div class="description">
                        <p>
                            {{ _(post.en_description) }}
                        </p>
                    </div>
                    {% for category in categories %}
                    <a class="ui grey label"> <i class="fas fa-globe"></i> {{ _(categories.en_name) }} </a>
                    {% endfor %}
                </div>

            </div>
            {% endfor %}
</div>

它应该提供类别的名称，但是我没有得到任何结果，只是空白处应该出现它们。预先感谢您的帮助。

Answer 1

您可能要使用在categories模型上创建的Post属性：

{% for category in post.categories %}

如何使用flask-sqlalchemy查询博客帖子的类别？

1 个答案: