从用户向一个或多个相关模型访问反向多个字段时出错

Question

我遇到了一个与用户模型有单一关系的模型类的问题，这是冲突的部分：

class UserInteraction(models.Model):
user = models.OneToOneField(User, related_name="interactions", on_delete=models.CASCADE)
users_follows = models.ManyToManyField('self', through='UserFollow', blank=True, symmetrical=False, related_name='user_follows')
users_likes = models.ManyToManyField('self', through='UserLike', blank=True, symmetrical=False, related_name='user_likes')

当我尝试通过user.interactions.user_follows或user.interactions.user_likes获得以下/点赞时，我会得到以下错误：

In [18]: u = User.objects.get(id=1)
In [19]: u.interactions.users_likes.all()
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
Input In [19], in <module>
----> 1 u.interactions.users_likes.all()
File ~...djangodbmodelsfieldsrelated_descriptors.py:536, in ReverseManyToOneDescriptor.__get__(self, instance, cls)
533 if instance is None:
534     return self
--> 536 return self.related_manager_cls(instance)
File ~...djangodbmodelsfieldsrelated_descriptors.py:826, in create_forward_many_to_many_manager.<locals>.ManyRelatedManager.__init__(self, instance)
824     self.prefetch_cache_name = rel.field.name
825     self.source_field_name = rel.field.m2m_field_name()
--> 826     self.target_field_name = rel.field.m2m_reverse_field_name()
827     self.symmetrical = rel.symmetrical
828 else:
File ~...djangodbmodelsfieldsrelated.py:1598, in ManyToManyField._get_m2m_reverse_attr(self, related, attr)
1596             setattr(self, cache_attr, getattr(f, attr))
1597             break
-> 1598 return getattr(self, cache_attr)
AttributeError: 'ManyToManyField' object has no attribute '_m2m_reverse_name_cache'

以下是在fk:中用于直通的跟随器和类似模型

class UserFollow(TimeStampBase):
follower = models.ForeignKey(User, on_delete=models.CASCADE, related_name='follower')
followed = models.ForeignKey(User, on_delete=models.CASCADE, related_name='followed')
class Meta:
constraints = [
models.UniqueConstraint(
name="%(app_label)s_%(class)s_unique_relationships",
fields=["followed", "follower"],
),
models.CheckConstraint(
name="%(app_label)s_%(class)s_prevent_self_follow",
check=~models.Q(follower=models.F("followed")),
),
]
def __str__(self):
return f'{self.follower} follows {self.followed}'

class UserLike(TimeStampBase):
liker = models.ForeignKey(User, on_delete=models.CASCADE, related_name='liker')
liked = models.ForeignKey(User, on_delete=models.CASCADE, related_name='liked')
class Meta:
constraints = [
models.UniqueConstraint(
name="%(app_label)s_%(class)s_unique_relationships",
fields=["liked", "liker"],
),
models.CheckConstraint(
name="%(app_label)s_%(class)s_prevent_self_follow",
check=~models.Q(liker=models.F("liked")),
),
]
def __str__(self):
return f'{self.liker} likes {self.liked}'

在管理中，一切都很好，我做错了什么？

Answer 1

直通模型中的ForeignKey字段需要引用包含ManyToManyField的模型，而不是OneToOneField中的模型-UserInteraction而不是User

class UserFollow(TimeStampBase):
follower = models.ForeignKey(UserInteraction, on_delete=models.CASCADE, related_name='follower')
followed = models.ForeignKey(UserInteraction, on_delete=models.CASCADE, related_name='followed')
...
class UserLike(TimeStampBase):
liker = models.ForeignKey(UserInteraction, on_delete=models.CASCADE, related_name='liker')
liked = models.ForeignKey(UserInteraction, on_delete=models.CASCADE, related_name='liked')
...