如何正確刪除特定的ManyToMany關係？

Question

我與我的一個模型有許多關係。在刪除一個孩子時，我想刪除這個關係，但留下記錄，因爲它可能正在被其他對象使用。在調用delete看法，我得到一個AttributeError錯誤：

Exception Value: 'QuerySet' object has no attribute 'clear'

這是我的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) 

而且views.py的相關章節：

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 

迴應你的評論。

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 

希望這會有所幫助！