从首页问答标题到问答详情页

主PY文件写视图函数，带id参数。 

@app.route('/detail/<question_id>')
def detail(question_id):
    quest = Question.query.filter(Question.id == question_id).first()
    return render_template('detail.html',ques=quest)

首页标题的标签做带参数的链接。

<a href="{{ url_for('detail',question_id = foo.id) }}">{{ foo.title }}</a>

在详情页将数据的显示在恰当的位置。 

{% for foo in questions %}
            <li class="list-group-item">
                <span class="glyphicon glyphicon-leaf" aria-hidden="true"></span>
                <a href="{{ url_for('detail',question_id = foo.id) }}">{{ foo.title }}</a>
                <p style="">{{ foo.detail }}</p>
                <span class="glyphicon glyphicon-user" aria-hidden="true"></span>
                <a href="">{{ foo.author.username }}</a>
                <span class="badge">{{ foo.creat_time }}</span>
  
            </li>
        {% endfor %}

建立评论的对象关系映射：

class Comment(db.Model):
    __tablename__ = 'comment'
    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
    author_id = db.Column(db.Integer,db.ForeignKey('user.id'))
    question_id = db.Column(db.Integer,db.ForeignKey('question.id'))
    creat_time = db.Column(db.DateTime,default=datetime.now)
    detail = db.Column(db.Text,nullable=False)
    question = db.relationship('Question',backref = db.backref('comments'))
    author = db.relationship('User',backref = db.backref('comments'))