【笔记】Django的ORM之删和改

Django ORM 数据库

一删除操作

1.视图层

<table border="1">
    <thead>
    <tr>
        <th>序号</th>
        <th>ID</th>
        <th>出版社名称</th>
        <th>操作</th>
    </tr>
    </thead>
    <tbody>
    {% for publisher in publisher_list %}
        <tr>
        <td>{{ forloop.counter }}</td>
        <td>{{ publisher.id }}</td>
        <td>{{ publisher.name }}</td>
       <td><ahref="/delete_publisher/?id={{ publisher.id }}">删除</a></td>
        <td><ahref="/edit_publisher/?id={{ publisher.id }}">编辑</a></td>
        </tr>
    {% endfor %}

    </tbody>
</table>

2. 逻辑层

通过GET方法向服务端传送要删除数据的id；

def delete_publisher(request):
    # 通过GET方法获取id
    del_id = request.GET.get('id', None)
    # 如果取到id，删除该数据并跳转到列表页，否则提示失败
    if del_id:
        # 通过id拿到药删除的数据对象
        del_obj = models.Publisher.objects.get(id=del_id)
        del_obj.delete()
        return redirect('/publisher_list/')
    else:
        return HttpResponse('删除失败，该出版社不存在')

二修改操作

1. 视图层

与上面一样

2. 逻辑层

def edit_publisher(request):
    # 如果是POST请求，说明是要更新出版社名称
    if request.method == 'POST':
        # 获取要更新的id
        edit_id = request.POST.get("id", None)
        # 获取新的名字
        new_name = request.POST.get("publisher_name")
        # 通过id获得出版社对象
        publisher_obj = models.Publisher.objects.get(id=edit_id)
        # 赋值新名字
        publisher_obj.name = new_name
        # 提交到数据库中执行
        publisher_obj.save()

        return redirect('/publisher_list/')

    edit_id = request.GET.get("id", None)
    if edit_id:
        publisher_obj = models.Publisher.objects.get(id=edit_id)
        return render(request, 'edit_publisher.html', {"publisher":publisher_obj})
    else:
        return HttpResponse('编辑的出版社不存在！')

三其他

1. 下拉框

<form action="/edit_book/" method="post">
    <input type="text" style="display: none" name="id" value="{{ edit_obj.id }}">
    <p>书名：
        <input type="text" name="book_title" value="{{ edit_obj.title }}">
    </p>
    <p>出版社名称：
        <select name="publisher">
            {% for publisher in all_publisher %}
                {% if edit_obj.publisher.id == publisher.id %}
                   <optionselectedvalue="{{ publisher.id }}">{{ publisher.name }}</option>
                {% else %}
                   <optionvalue="{{ publisher.id }}">{{ publisher.name }}</option>
                {% endif %}
            {% endfor %}
        </select>
    </p>
    <p>
        <input type="submit" value="提交">
    </p>
</form>