如何删除Sqlite中的记录 [英] How to delete record in Sqlite

问题描述

我正在使用Flask的教程应用程序学习Python，我无法想象如何引用数据库中的某一行。我试图通过使用模板中的删除链接删除一条记录。我花了一整天的尝试，我能找到的一切，真正理解这一点。我知道这很简单，但我不明白！

以下是html模板：

 < ul class = entries> 
 {％用于输入条目％} 
< li>< h2> {{entry.title}} 
< h2> {{entry.text | safe}}< / H2> 
 {％if session.logged_in％} 
< a href ={{url_for（'delete_entry'）}}>删除< / a> 
 {％endif％} 
 {％else％} 
 {％endfor％} 
< / ul> 
  

正如您所看到的，每个条目旁边都有一个删除链接。我应该如何引用
在数据库中的正确id？

以下是我到目前为止的Python函数：

<$ p $ （）：
中断（401）
g.db.execute（'delete from entries where id =（select max（id）from entries）'）
g.db.commit（）
flash（'条目已被删除'）
return redirect（url_for（'show_entries'））

作品，但这不是我想要的。提前致谢！

解决方案

Sebastien的delete_entry函数正在删除db中的最后一个条目

< > 其中id =（从条目中选择max（id））

您需要做的是插入参数在url中删除，像'/ delete /：id'，其中id是要删除的条目的id，然后更改模板以生成url：

 < a href ={{url_for（'delete_entry'，entry.id）}}>删除< / a> 
  

还要更改删除条目的db查询：

  g.db.execute（'delete from entries where id ='+ id）
  

Edit1：

我检查了Flask文档，为了获得变量到你的路由中，你必须修改路由如下：

  @ app.route（'/ delete /< int：entry_id>'）
  
 
 
  def delete_entry（entry_id）：
 g.db.execute（'delete from entries where id ='+ entry_id）
  
最后，您必须在url_for函数中指定您的入口ID： 
 
 
  < a href ={{url_for（'delete_entry'，entry_id = entry.id）}}>删除< / a> 
  
 
I'm learning Python with the tutorial app from Flask and I can't figure how to reference a certain row in the database. I m trying to delete a record by using the delete link in the template.I spent a whole day trying everything I could find and to really understand this. I know it's simple but I don't get it!


Here's the html template:
<ul class=entries>
{% for entry in entries %}
<li><h2>{{ entry.title }}
<h2>{{ entry.text|safe }}</h2>
{% if session.logged_in %}
<a href="{{ url_for('delete_entry') }}">Delete</a>
{% endif %}
{% else %}
{% endfor %}
</ul>
As you can see, next to each entry there's a delete link.How am I supposed to reference the
right id in the database?

Here's the Python function I have so far:
@app.route('/delete')
def delete_entry():
if not session.get('logged_in'):
    abort(401)
g.db.execute('delete from entries where id=(select max(id)from entries)') 
g.db.commit()
flash('The entry was deleted')
return redirect(url_for('show_entries'))
What I have so far works but It's not what I want. Thanks in advance!      
解决方案
Sebastien the delete_entry function is deleting the last entry in the db 

where id=(select max(id)from entries)

What you have to do is insert a parameter in the url for deletion like '/delete/:id' where the id is the id of the entry you want deleted, then change the template to generate the url as so:
<a href="{{ url_for('delete_entry', entry.id) }}">Delete</a>
And also change the db query that deletes the entry:
g.db.execute('delete from entries where id=' + id)
Edit1:

I checked the Flask documentation, in order to get variables into your routes you have to modify the route as follows:
@app.route('/delete/<int:entry_id>')
In this way you obtain the entry_id in your python function:
def delete_entry(entry_id):
g.db.execute('delete from entries where id=' + entry_id)
And finally you have to specify your entry id in the url_for function:
<a href="{{ url_for('delete_entry', entry_id = entry.id) }}">Delete</a>


                        
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