查询扩展用户模型返回错误

Posted 2021-05-06

我在进行以下查询时收到错误：

Election.objects.all().exclude(candidate__UserID=request.user).filter(Gender=request.user.Profile.Gender).filter(CandidateReg=True)

对于这个模型：

class Election(models.Model):
    Name = models.CharField(max_length=20)
    CandidateReg = models.BooleanField(default=True)
    VotingOpen = models.BooleanField(default=False)
    Description = models.CharField(max_length=255, null=True, blank=True)
    GENDERS = (("M","Male"), ("F","Female"))
    Gender = models.CharField(max_length=1, choices=GENDERS, default="M")
    Seats = models.IntegerField(default=7)
    FlipGrid = models.URLField(null=True, blank=True)
    Complete = models.BooleanField(default=False)

此错误中描述了此问题：

Traceback (most recent call last):
      File "/home/elections/venv/lib/python3.6/site-packages/django/core/handlers/exception.py", line 41, in inner
        response = get_response(request)
      File "/home/elections/venv/lib/python3.6/site-packages/django/core/handlers/base.py", line 187, in _get_response
        response = self.process_exception_by_middleware(e, request)
      File "/home/elections/venv/lib/python3.6/site-packages/django/core/handlers/base.py", line 185, in _get_response
        response = wrapped_callback(request, *callback_args, **callback_kwargs)
      File "/home/elections/elections-real/elections/views.py", line 139, in add_candidate
        elections = Election.objects.all().exclude(candidate__UserID=request.user).filter(Gender=request.user.Profile.Gender).filter(CandidateReg=True)
      File "/home/elections/venv/lib/python3.6/site-packages/django/utils/functional.py", line 239, in inner
        return func(self._wrapped, *args)
    AttributeError: 'User' object has no attribute 'Profile'

它似乎表明问题是在当前用户的配置文件中引用Genderdata - 用户模型的扩展。这显示在这里：

class Profile(models.Model):
    UserID = models.OneToOneField(User, on_delete=models.CASCADE)
    GENDERS = (("M","Male"), ("F","Female"))
    Gender = models.CharField(max_length=1, choices=GENDERS)
    UserTypeID = models.ForeignKey(UserType, on_delete=models.PROTECT, blank=True, null=True)
    EmailConfirmed = models.BooleanField(default=False)

@receiver(post_save, sender=User)
def create_user_profile(sender, instance, created, **kwargs):
    if created:
        Profile.objects.create(UserID=instance)

@receiver(post_save, sender=User)
def save_user_profile(sender, instance, **kwargs):
    instance.profile.save()

如果不按上述方式，如何正确引用登录用户配置文件的Gender属性？

答案

一对一字段的反向访问器始终是模型的低级名称：因此它将是request.user.profile...。

如果您遵循标准的PEP-8兼容样式并用小写字母命名所有字段 - gender，voting_open，email_confirmed等，那么这对您来说就不那么令人惊讶了。另请注意，给出以ID结尾的关系字段名称不是最佳做法访问整个相关对象，而不仅仅是ID，所以你的UserID应该被称为user。

最后，关于性别，请阅读Falsehoods Programmers believe about Gender并考虑您是否真的需要询问此信息。