如何正确删除特定的ManyToMany关系？

Question

我与我的一个模特有一个ManyToMany关系.在删除子项时,我想删除该关系,但保留其他对象可能正在使用的记录.在调用删除视图时,我收到AttributeError错误:

异常值:'QuerySet'对象没有属性'clear'

这是我的models.py:

class Feed(models.Model):
    username = models.CharField(max_length=255, unique=True)

class Digest(models.Model):
    name = models.CharField(max_length=255)
    user = models.ForeignKey(User)
    items = models.PositiveIntegerField()
    keywords = models.CharField(max_length=255, null=True, blank=True)
    digest_id = models.CharField(max_length=20, unique=True)
    time_added = models.DateTimeField(auto_now_add=True)
    active = models.BooleanField(default=1)
    feeds = models.ManyToManyField(Feed)

以及views.py的相关部分:

def feed_delete(request, id):
    digest = get_object_or_404(Digest, id=id)
    if digest.user == request.user:
        Feed.objects.get(id=request.POST.get('id')).digest_set.filter(id=id).clear()

    return HttpResponseRedirect(digest.get_absolute_url())

Answer 1

清除Digest isntance上的字段

digest = get_object_or_404(Digest, id=id)
if digest.user == request.user:
  digest.feeds.clear()
  #do your processing

回应你的评论.

digest = get_object_or_404(Digest, id=id)
if digest.user == request.user:
  feed=digest.feeds.get(id=2)#get an instance of the feed to remove
  digest.feeds.remove(feed)#remove the instance 

希望这可以帮助!