Why I am getting Error: 'QuerySet' object has no attribute?

Question

我有 3 个模型

class Lease(CommonInfo):
    version = IntegerVersionField( )
    #amount  = models.DecimalField(max_digits=7, decimal_places=2)
    is_renewed = models.BooleanField(default=False)
    unit = models.ForeignKey(Unit)
    is_terminated = models.BooleanField(default=False)

class LeaseTerm(CommonInfo):
    version = IntegerVersionField( )
    start_period = models.ForeignKey(Period, related_name='start_period' )
    end_period = models.ForeignKey(Period, related_name='end_period')
    lease = models.ForeignKey(Lease)
    increase  = models.DecimalField(max_digits=7, decimal_places=2)
    amount  = models.DecimalField(max_digits=7, decimal_places=2)
    is_terminated = models.BooleanField(default=False)

    def clean(self):
    model = self.__class__
    if self.lease_id and (self.is_terminated == False) and model.objects.filter(lease=self.lease, is_active=True ).count() == 1:
        raise ValidationError('!Lease has a active condition already, Terminate prior to creation of new one'.format(self.lease))

class LeasePayment(CommonInfo):
    version = IntegerVersionField( )
    amount  = models.DecimalField(max_digits=7, decimal_places=2)
    leaseterm = models.ForeignKey(LeaseTerm)
    period_payed_for = models.DateTimeField()
    payment_date = models.DateTimeField()

(clean方法只允许一个LeaseTerm处于活动状态且不终止。)

在我看来，我想查看此租约的有效 LeaseTerm 的所有付款

    lease = get_object_or_404(Lease, pk=lease_id)
    leaseterm = LeaseTerm.objects.filter(lease=lease, is_terminated =False, is_active = True )
    payment = leaseterm.leasepayment_set.all().order_by('payment_date')

但出现错误

'QuerySet' object has no attribute 'leasepayment_set'

我做错了什么？

Answer 1

模型 LeaseTerm 的一个实例具有属性 leasepayment_set，而不是模型 LeaseTerm 的查询集。您可以通过获取这些实例来访问 leasepayment_set。

get 而不是 filter

leaseterm = LeaseTerm.objects.get(lease=lease, ...)
payment = leaseterm.leasepayment_set.all()

围绕查询集循环

leaseterm = LeaseTerm.objects.filter(lease=lease, ...)
for lt in leaseterm: # lt is an instance of LeaseTerm
    payment = lt.leasepayment_set.all()

（通过评论更新，感谢Alasdair和Ingomar）从相关模型开始，查询表达式更高效优雅。
```
LeasePayment.objects.filter(leaseterm__lease=lease)
```

Why I am getting Error: 'QuerySet' object has no attribute?

Why I am getting Error: 'QuerySet' object has no attribute?

django

django-queryset