Django数据更新操作记住一下顺口溜：

对于修改一条数据，要一查二改三保存。对于批量数据，只要拿到一组queryset然后直接update即可，

思路：

前端传过来一个id，后端根据这个id获取数据并把数据返给前端，前端在本地更新需要修改的数据后回传给后端，后端接到值后更新数据库

示例：

1pc后台页面有一个更新按钮

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<table border="1" cellspacing=0 >
  <tr bgcolor="#d3d3d3">
    <th>id</th>
    <th>title</th>
    <th>pub</th>
    <th>price</th>
    <th>market_price</th>
    <th>op</th>
  </tr>
    {% for book in data_book %}
      <tr>
        <td>{{ book.id }}</td>
        <td>{{ book.title }}</td>
        <td>{{ book.pub }}</td>
        <td>{{ book.price }}</td>
        <td>{{ book.market_price }}</td>
        <td>
            <a href="/bookstore/update_book/{{ book.id }}">更新</a>
            <a>删除</a>
        </td>
      </tr>
    {% endfor %}
</table>

</body>
</html>

2触发更新按钮弹出的页面：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>更改书籍</title>
</head>
<body>
<form action="/bookstore/update_book/{{ book.id }}" method="post">
    <p>
        title <input type="text" value="{{ book.id }}" disabled="disabled">
    </p>
    <p>
        pub <input type="text" value="{{ book.pub }}" disabled="disabled">
    </p>
    <p>
        price <input type="text" value="{{ book.price }}" name="price">
    </p>
    <p>
        market_price <input type="text" value="{{ book.market_price }}" name="market_price">
    </p>
    <p>
        <input type="submit" value="更新">
    </p>
</form>
</body>
</html>

3后台定义更新页面的路由：

path('update_book/<int:book_id>',views.update_book),

4编写路由绑定的视图函数：

#更新书籍
def update_book(request, book_id):
    try:
        book = Book.objects.get(id=book_id) # #获取不到值会报错，所以加了try...except
    except Exception as e:
        print('--update book error is %s'%(e))
        return HttpResponse('--The book is not existed')
    if request.method == 'GET':
        return render(request,'bookstore/update_book.html',locals())
    elif request.method == 'POST':
        #获取
        price = request.POST['price']
        market_price = request.POST['market_price']
        #修改
        book.price = price
        book.market_price = market_price
        #保存
        book.save()
        return HttpResponseRedirect('/bookstore/all_book')