Question

我正在学习一些教程，但是当教师说我应该将评论中的外键放到帖子上以便得到评论时，我们没有得到。而不是comment_set，我做了

#path = request.get_full_path()
#comments = Comment.objects.filter(path=path)

现在，当我不应该给孩子发表评论时，我会得到孩子评论。当我执行post.comment_set.all(),而非上述两行时，我不会发表任何评论和此错误;＆＃39;发布＆＃39;对象没有属性＆＃39; comment_set＆＃39; 。有人可以澄清comments = post.comment_set.filter的工作原理吗？这是我的完整代码。

models.py

class Comment(models.Model):
    user = models.ForeignKey(MyProfile)
    parent = models.ForeignKey("self", null=True, blank=True)
    path = models.CharField(max_length=350)
    post = models.ForeignKey(Post, null=True, blank=True, related_name="commented_post")
    text = models.TextField()
    updated = models.DateTimeField(auto_now=True, auto_now_add=False)
    timestamp = models.DateTimeField(auto_now=False, auto_now_add=True)
    active = models.BooleanField(default=True)

    objects = CommentManager()

    class Meta:
        ordering = ['-timestamp']

    def __unicode__(self):
        return self.text


    def get_absolute_url(self):
        return reverse('comment_thread', kwargs={"id": self.id})

    @property 
    def get_origin(self):
        return self.path

    @property
    def get_comment(self):
        return self.text

    @property
    def is_child(self):
        if self.parent is not None:
            return True
        else:
            return False

    def get_children(self):
        if self.is_child:
            return None
        else:
            return Comment.objects.filter(parent=self)

和我的views.py

#for single-post page
def post(request, slug):
        user = get_object_or_404(User,username__iexact=request.user)
        try:
            profile = MyProfile.objects.get(user_id=request.user.id)
            # if it's a OneToOne field, you can do:
            # profile = request.user.myprofile
        except MyProfile.DoesNotExist:
            profile = None


        post = get_object_or_404(Post, slug=slug)
        post.views += 1  # increment the number of views
        post.save()      # and save it

        #path = request.get_full_path()
        #comments = Comment.objects.filter(path=path)
        comments = post.comment_set.all()
        comment_form = CommentForm(request.POST or None)
        for c in comments:
                c.get_children()

        context_dict = {
            'post' :post,
            'profile' :profile,
            'comments' : comments,
            'comment_form':comment_form
        }
        return render(request, 'main/post.html', context_dict)

Answer 1

Django支持所谓的＆＃34;后向关系＆＃34;，它只是从实体对象向后访问子实体。让我们说我们有下一个模型：

class Post(models.Model):
    #some fields

class Comment(models.Model):
    post = models.ForeignKey(Post)

然后Django为您提供默认function以通过post.comment_set语句访问Comment。但是，如果要在外键的注释中编写related_name选项，它会将此默认comment_set更改为...您在related_name选项中编写的内容。你可以阅读这个here。那就是你写的

post = models.ForeignKey(Post, null=True, blank=True, related_name="commented_post")

这意味着您必须通过

访问您的评论

post.commented_post.all()

希望它有所帮助！

＆＃39;后＆＃39;对象没有属性＆＃39; comment_set＆＃39;由post.comment_set.all（）引起，当comment_set是外键时它是什么意思？

1 个答案: