如何检查模型是否在模型外键集中？ django，django rest框架

Question

我有一个与场地具有多对一关系的房间模型。

一个场地可以有很多房间。

我正在尝试在我的 rest 框架中设置我的 http 方法，这样当我添加权限时，一切都会正常工作。

所以如果说有人想从场地中删除一个房间，我必须确保 1 该人有权访问该场所 2那个房间附属于那个场地

我想要一个场地模型 然后获取场地模型 room_set 并检查 room_set 以查看是否存在带有我要删除的模型的房间主键的房间。

到目前为止我所拥有的：

class GetEditDeleteVenueRoom(APIView):

    def get(self, request, *args, **kwargs):
        pass

    def post(self, request, *args, **kwargs):
        print('wait its over here')



    def delete(self, request, *args, **kwargs):
        venuepk = kwargs.get('venuepk', None)
        venue = get_object_or_404(Venue, pk=venuepk)
        venuerooms = venue.room_set
        print(venuerooms)
        return Response({})

我希望我可以交互场地房间并检查场地房间中的每个对象，但我有一种强烈的感觉，因为场地房间不是 python 对象，所以它不会工作？也许是的。我将在执行 for 循环后更新这个问题，或者如果我发现一切正常，我可能会删除它。

我的问题是如何设置房间并检查是否包含我正在搜索的 roompk 的房间。

正如我所料，我尝试的代码出错了：

def delete(self, request, *args, **kwargs):
    venuepk = kwargs.get('venuepk', None)
    venue = get_object_or_404(Venue, pk=venuepk)
    venuerooms = venue.room_set
    roompk = kwargs.get('roompk')
    roomobject = None
    for room in venuerooms:
        if room.pk == roompk:
            roomobject = room
    roomobject.delete()

    print(venuerooms)
    return Response({})

我得到的错误：

File "/home/rickus/Documents/softwareProjects/211hospitality/suitsandtables/backend/virtualsuits/suitsandtables/venues/views.py", line 125, in delete
    for room in venuerooms:
TypeError: 'RelatedManager' object is not iterable

对我能做什么有什么想法吗？

新编辑：

所以我实现了下面的答案并将all() 添加到我的场地房间定义中

但现在我有一个新错误。这个没有意义，因为我显然在 for 循环中覆盖了 None 属性。

def delete(self, request, *args, **kwargs):
        venuepk = kwargs.get('venuepk', None)
        venue = get_object_or_404(Venue, pk=venuepk)
        venuerooms = venue.room_set.all()
        roompk = kwargs.get('roompk')
        roomobject = None
        for room in venuerooms:
            if room.pk == roompk:
                print(room)
                roomobject = room
        roomobject.delete()

        print(venuerooms)
        return Response({})

错误：

File "/home/rickus/Documents/softwareProjects/211hospitality/suitsandtables/backend/virtualsuits/suitsandtables/venues/views.py", line 129, in delete
    roomobject.delete()
AttributeError: 'NoneType' object has no attribute 'delete'
[14/Mar/2018 20:01:53] "DELETE /api/suitsadmin/venue/1/room/15 HTTP/1.1

Answer 1

添加您的模型以帮助解决问题....但这是您访问 room_set 的方式

def delete(self, request, *args, **kwargs):
    venuepk = kwargs.get('venuepk', None)
    venue = get_object_or_404(Venue, pk=venuepk)
    roompk = kwargs.get('roompk')
    room = venue.room_set.filter(pk=roompk)
    room.delete()
    return Response({})

Answer 2

所以我最终这样做了：

我在房间组中找到房间对象后就抓住它。通过查询房间对象的数据库。不过，我对这个答案并不满意。正如我想象的那样， room_set 已经可以访问房间对象了？我不能就这样删除它吗？如果可以的话，我会很感激比我更好的答案。无论如何，这就是我所做的。

 def delete(self, request, *args, **kwargs):
        venuepk = kwargs.get('venuepk', None)
        venue = get_object_or_404(Venue, pk=venuepk)
        venuerooms = venue.room_set.all()
        roompk = kwargs.get('roompk')
        roomobject = None
        for room in venuerooms:
            if room.pk == roompk:
               roomobject = Room.objects.get(pk=roompk)
               roomobject.delete()
               return Response({})

        return Response(status.HTTP_404_NOT_FOUND)