爲什麼我得到錯誤：'QuerySet'對象沒有屬性？

Question

我有3種型號

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() 

（清潔方法只允許一個LeaseTerm被激活，而不是終止。）

在我看來，我想看看這個租賃公司積極LeaseTerm所做的所有款項

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') 

，但得到一個錯誤

'QuerySet' object has no attribute 'leasepayment_set'

我做錯了什麼？

Answer 1

模型LeaseTerm的實例具有屬性leasepayment_set，而不是模型LeaseTerm的查詢集。您可以通過獲取像這樣的實例來訪問leasepayment_set。

1. get，而不是filter

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

2. 周圍的查詢集循環

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

3. （通過評論更新，感謝麥金太爾和Ingomar）開始與相關的模型，它是更高效和優雅的查詢表達式。

   LeasePayment.objects.filter(leaseterm__lease=lease)