Question

I have a four classes:

class A(models.Model):
    field1 = models.BooleanField(default = True)

    class Meta:
        abstract = True


class B(models.Model):
    field2 = models.BooleanField(default = True)
    sites = models.ManyToManyField(Site)

    class Meta:
        abstract = True

class C(A,B):
    field3 = models.BooleanField(default = True)

    class Meta:
        abstract = True

and

class D(C):
    field4 = models.BooleanField(default = True)

Only class D is in models.py in my app. Others is imported from diffrent files. Fields of classess A anb B are being used in many models. I created class D because i want to have generic admin panel from Django.

However, if i use this code:

obj = D()
model_class = obj.__class__
items = model_class.objects.filter(sites__id__exac=1)

i get the error:

Join on field 'id' not permitted. Did you misspell 'exac' for the lookup type?

Why?

Answer 1

You’re missing a few letters:

https://docs.djangoproject.com/en/1.3/ref/models/querysets/#exact

More importantly, you shouldn’t need to do an __exact on an ID field, just do:

items = model_class.objects.filter(sites__id=1)

or

items = model_class.objects.filter(sites__id__in=[1])