从首页问答标题到问答详情页

1. 主PY文件写视图函数，带id参数。 

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

    

2. 首页标题的标签做带参数的链接。
         {{ url_for('detail',question_id = foo.id) }}
   
   
3. 在详情页将数据的显示在恰当的位置。 

   {{ ques.title}}
   {{ ques.id  }}{{  ques.creat_time }}

   {{ ques.author.username }} 
   {{ ques.detail }}

4. 建立评论的对象关系映射：

   class Comment(db.Model):
       __tablename__='comment'

5.  尝试实现发布评论。

   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'))

   <input type="hidden" name="question_id" value="{{ ques.id }}">

   @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)

   {% extends 'daohang.html' %}
   {% block title %}问答详情{% endblock %}
   
   {% block main %}
       <div class="page-header">
           <h3>Title {{ ques.title }}<br><small>{{ ques.author.username }} <span class="badge">{{ ques.creat_time }}</span></small>></h3>
       </div>
       <p class="lead">detail{{ ques.detail }}</p>
       <hr>
   
       <form action="{{ url_for('question') }}"method="post" style="...">
           <div class="form-group">
               <textarea name="new_comment" id="new-comment" class="form-control" rows="3"
                         placeholder="write your comment"></textarea>
               <input type="hidden" name="question_id" value="{{ ques.id }}">
           </div>
           <button type="submit" class="btn btn-default">发送</button>
       </form>
       <h4>评论:({{ ques.comments|length }})</h4>>
       <ul class="list-group" style="margin:10px"></ul>>
   {% endblock %}