我正在嘗試為學(xué)生制作一個(gè)應(yīng)用程序，但我收到了此錯(cuò)誤，正如您所看到的，為了方便起見(jiàn)，我想使用如下所示的應(yīng)用程序，但它不起作用，我應(yīng)該像以前一樣繼續(xù)使用嗎？或者我可以這樣使用？最好的辦法是什么？/student/program_struct/ 處的 ValueError 無(wú)法查詢“ abcd@gmail.com ”：必須是“學(xué)生”實(shí)例。太感謝了 ：）models.pyclass Student(models.Model):    user = models.ForeignKey(          settings.AUTH_USER_MODEL, on_delete=models.CASCADE, null=True)    status = models.CharField(max_length=10, choices=STATUS, default='active')  class Program(models.Model):                 #everything was fine when used     user = models.ForeignKey(          settings.AUTH_USER_MODEL, on_delete=models.CASCADE, null=True)  #this one         #but when using this one i started getting this error from views.py     user = models.ForeignKey(                  Student, on_delete=models.SET_NULL, null=True)    name = models.CharField(max_length=200, unique=True)    prefix = models.CharField(max_length=20)class Course(models.Model):    user = models.ForeignKey(Student, on_delete=models.SET_NULL, null=True)    name = models.CharField(max_length=200, unique=True)    prefix = models.CharField(max_length=20)    code = models.CharField(max_length=20)   subject = models.ManyToManyField('Subject', related_name='subject_list',                   blank=True)views.py       class Program_structure(generic.View):    def get(self, *args, **kwargs):        profile = get_object_or_404(Student, user=self.request.user)        program_structure = Course.objects.filter(student=profile)         # program_structure =         Course.objects.filter(student__user=self.request.user)        credit = Course.objects.filter(student__user=self.request.user).           annotate(total_no=Sum('subject__credit'))        total_credit = self.request.user.course_set.aggregate(             total_credit=Sum('subject__credit')           )['total_credit'] or 0     context = {        'test':program_structure,        'credit':credit,        'profile':profile,        'total_credit' : total_credit    }    return render(self.request, 'program_structure.html', context)