Django模型不能保存查询

Question

我一直在Django工作了一段时间，现在我遇到了这个奇怪的问题。

我在流网站增加一个等级的功能，为此，我写了一个是通过URL称为视图：

url(r'^channel/rate/(?P<stream_id>[\d]*)/(?P<rate>[\d]*)/?$', 'eros.streaming.views.view_rate_channel', 
    name='view_rate_channel'), 

def view_rate_channel(request,stream_id,rate): 
    if(stream_id and rate and request.user.is_authenticated()): 
     stream= Stream.objects.get(id=stream_id) 
     if stream not in request.user.channel.rated_streams.all(): 
      if stream.channel.user != request.user: 
       channel=Channel.objects.get(stream=stream) 
       channel.rating= channel.rating+int(rate)  
       print("channel rating: "+str(channel.rating)) 
       #this prints fine in any case 
       channel.n_voters = channel.n_voters +1 
       channel.save() 
       stream.rating= stream.rating+int(rate) 
       stream.n_voters= stream.n_voters+1 
       stream.save()  
       request.user.channel.rated_streams.add(stream) 
       request.user.channel.save() 
       return HttpResponseRedirect('/channel/'+str(stream.channel.id)+'/') 
    return HttpResponseRedirect('/channel/'+str(stream.channel.id)+'/') 

当我检查了数据库，改变我的频道即将播出channel.save（）之后的对象没有保存，只有Stream对象发生了奇怪的变化。

所以做一些调试完毕后，我决定发表评论这个如果我使用，因此用户不能率流不止一次：

 ##if stream not in request.user.channel.rated_streams.all(): 

而且现在channel.save（）的工作！坏事是我不能让用户不止一次地评价一个流。

继承人的模型的简化版本：

class Channel(models.Model): 
    user = models.OneToOneField(User) 
    rating = models.IntegerField(default=0) 
    n_voters = models.IntegerField(default=0) 
    rated_streams = models.ManyToManyField('Stream', related_name="rated_streams") 
    description = models.TextField(default="") 

class Stream(models.Model): 
    ## I think that maybe this relation is what is causing me trouble (?): 
    channel = models.ForeignKey(Channel) 
    rating = models.IntegerField(default=0) 
    n_voters = models.IntegerField(default=0) 

有什么不好的做法或坏的查询，我做的是正在发生的呢？提前致谢。

Answer 1

使用channel = stream.channel代替channel = Channel.objects.get(stream=stream)修复了此问题。