从父查询集中检索 prefetch_related 对象的平面查询集

Question

If I have models like so:

class A(models.Model):
  ...


class B(models.Model):
  a = models.ForeignKey(A)


class C(models.Model): 
  b = models..ForeignKey(B)

I can get the full queryset:

qs = A.objects.all().prefetch_related('b_set', 'b_set__c_set')
>> <QuerySet [<A: A object (1)>, <A: A object (2)>, ... ]>

What I want to know is there a way to get all the C objects in a flattened queryset, eg:

qs['b_set__c_set']
>> <QuerySet [<C: C object (1)>, <C: C object (2)>, ... ]>

Answer 1

You could do a query on the C Model, just checking for all C's that have an a value? So

C.objects.filter(b__is_null=False, b__a__isnull=False)

Would that achieve what you're looking for?