ReverseSingleRelatedObjectDescriptor对象没有属性'username'

Question

我有一个模特评论：

class Comment(models.Model):
    text = models.CharField(max_length=140)
    owner = models.ForeignKey(User, null=True, blank=True)
    created = models.DateTimeField(default=datetime.datetime.utcnow)

当我尝试创建注释时，我得到一个AttributeError：

ipdb> usr = User.objects.get(pk=1)
ipdb> usr
<User: admin>
ipdb> Comment.objects.create(owner=usr)
*** AttributeError: 'ReverseSingleRelatedObjectDescriptor' object has no attribute 'username'
ipdb> usr.username
u'admin'
ipdb> 

Answer 1

我也有这个追溯：

'ReverseSingleRelatedObjectDescriptor' object has no attribute my_attribute

我找到了解决方案：

Comment.user # Access on class level: does raise the above error

comment.user # Access on instance: this works!