AttributeError：“DeferredAttribute”对象没有属性“对象”

Question

我收到一个错误，AttributeError: 'DeferredAttribute' 对象没有属性 'objects'。 我想解析excel并将其放入模型（City&Prefecture&Area&User）。我写了

user3 = User.objects.filter(corporation_id=val3).first()
if user3:
   area = Area.objects.filter(name="America").first()
   pref = Prefecture.objects.create(name="prefecture", area=user3.area)
   city = City.objects.create(name="city", prefecture=pref)
   price_u1000 = Price.upper1000.objects.get(city=city)
   price_500_1000 = Price.from500to1000.objects.get(city=city)
   price_u500 = Price.under500.objects.get(city=city)

   pref.name = "NY"
   pref.save()

   for i in range(2,len(fourrows_transpose)):
       city.name = fourrows_transpose[i][1]
       city.save()
       print(fourrows_transpose[i][1])

       price_u1000.name = fourrows_transpose[i][2]
       price_u1000.save()
       print(fourrows_transpose[i][2])

       price_500_1000.name = fourrows_transpose[i][3]
       price_500_1000.save()
       print(fourrows_transpose[i][3])

       price_u500.name = fourrows_transpose[i][4]
       price_u500.save()
       print(fourrows_transpose[i][4])

Traceback 说这个代码price_u1000 = Price.upper700.objects.get(city=city) 是错误的。 models.py 是

class Area(models.Model):
    name = models.CharField(max_length=20, verbose_name='area', null=True)
class User(models.Model):
    user_id = models.CharField(max_length=200,null=True)
    area = models.ForeignKey('Area',null=True, blank=True)

class Prefecture(models.Model):
    name = models.CharField(max_length=20, verbose_name='prefecture')
    area = models.ForeignKey('Area', null=True, blank=True)

class City(models.Model):
    name = models.CharField(max_length=20, verbose_name='city')
    prefecture = models.ForeignKey('Prefecture', null=True, blank=True)

class Price(models.Model):
    upper1000 = models.CharField(max_length=20, verbose_name='u1000', null=True)
    from500to1000 = models.CharField(max_length=20, verbose_name='500～1000', null=True)
    under500 = models.CharField(max_length=20, verbose_name='d500', null=True)
    city = models.ForeignKey('City', null=True, blank=True)

我应该怎么做才能解决这个问题？我应该怎么写？

Answer 1

这是因为upper1000 或任何字段没有属性对象。对象存在于模型类中。

如果upper1000、from500to1000 和under500 是互斥的，你可以这样做。但请记住，如果是这种情况，您应该在模型清理函数中处理互斥性。

price_u1000 = Price.objects.filter(city=city, upper1000__isnull=False, from500to1000__isnull=True, under500__isnull=True)

我建议创建一个选择字段，而不是 3 个似乎互斥的不同字段

class Price(models.Model):

    UNDER_500 = 'under 500'
    FROM_500_TO_1000 = 'from 500 to 1000'
    UPPER_1000 = 'upper 1000'

    PRICE_CHOICES = [
        (UNDER_500, pgettext_lazy('Price under 500')),
        (FROM_500_TO_1000, pgettext_lazy('Price from 500 to 1000')),
        (UPPER_1000, pgettext_lazy('Price above 1000'))
    ]

    price_range = models.CharField(
        verbose_name=ugettext_lazy('Price range'),
        max_length=25,
        choices=PRICE_CHOICES,
        default=UNDER_500
    )

    city = models.ForeignKey('City', null=True, blank=True)

    def clean(self):
        super(Price, self).clean()
        # implement extra constraints here.

一些读数： https://docs.djangoproject.com/en/1.11/ref/models/querysets/