在 Django 的 Python2.x 类上使用 super()

Question

我的 models.py 看起来像这样：

class Prescription(models.Model):
    date_prescribed = models.DateTimeField()
    doctor = models.ForeignKey(Doctor)  
    pharmacy = models.ForeignKey(Pharmacy)

class Doctor(models.Model):
    name = models.CharField(max_length=150)  
    age = models.PositiveSmallIntegerField()

class Pharmacy(models.Model):
    name = models.CharField(max_length=150)
    status = models.CharField()

在我看来，我希望按 month.I 分组的处方数我正在使用 Django rest framework.My views.py 如下：

class PrescriptionTrendListView(generics.ListAPIView):
    queryset = Prescription.objects.all()
    serializer_class = LineGraphSerializer

    def get_queryset(self):
        end_date = timezone.now()
        start_date = end_date - relativedelta(months=6)
        truncate_date = connection.ops.date_trunc_sql('month', 'date_prescribed')
        qs = super().get_queryset.extra(select={'month': truncate_date})
        return qs.filter(date_prescribed__range=(start_date, end_date)
        ).annotate(pk_count=Count('pk')).order_by('month')


    def get(self, request, *args, **kwargs):
        graph_data = self.get_queryset().values('pk_count', 'month')
        serializer = self.get_serializer(data=graph_data, many=True)
        return Response(serializer.data)

但是，当我运行这是我得到的错误是：

我假设这与 Python 3 中的新样式类有关2.x ?

Answer 1

在 Python 2 中，super 的语法是这样的：

class MyClass(Base):
    def func(self, *args, **kwargs):
        super(MyClass, self).func(*args, **kwargs)

Answer 2

这真的很愚蠢，但我怀疑这是因为您在声明 Doctor 和 Pharmacy 之前引用了它们。试试这个：

class Doctor(models.Model):
    name = models.CharField(max_length=150)  
    age = models.PositiveSmallIntegerField()

class Pharmacy(models.Model):
    name = models.CharField(max_length=150)
    status = models.CharField()
class Prescription(models.Model):
    date_prescribed = models.DateTimeField()
    doctor = models.ForeignKey(Doctor)  
    pharmacy = models.ForeignKey(Pharmacy)

我在 Python 2.x 上查看了我的一些旧 Django，你的模型看起来不错，只是这似乎是个问题（？）

Answer 3

您在 get_queryset 中的 super() 调用缺少 type 和 self 参数。

class PrescriptionTrendListView(generics.ListAPIView):
    queryset = Prescription.objects.all()
    serializer_class = LineGraphSerializer

    def get_queryset(self):
        end_date = timezone.now()
        start_date = end_date - relativedelta(months=6)
        truncate_date = connection.ops.date_trunc_sql('month', 'date_prescribed')
        # Bug was here
        qs = super(PrescriptionTrendListView, self).get_queryset.extra(select={'month': truncate_date})
        return qs.filter(date_prescribed__range=(start_date, end_date)
        ).annotate(pk_count=Count('pk')).order_by('month')


    def get(self, request, *args, **kwargs):
        graph_data = self.get_queryset().values('pk_count', 'month')
        serializer = self.get_serializer(data=graph_data, many=True)
        return Response(serializer.data)

https://docs.python.org/2/library/functions.html#super

在 Django 的 Python2.x 类上使用 super()

Using super() on Python2.x classes in Django

python

django

class

super

在 Django 的 Python2.x 类 上使用 super()

Using super() on Python2.x classes in Django

python

django

class

super

在 Django 的 Python2.x 类上使用 super()