I have following models :

ModelA –> with fields flda1, flda2, fld3 and id

ModelB –> with fields fldb1, fldb2, id and a_obj = foreign-key-to-ModelA

Now I have to write view to update flda1 and flda2 of ModelA and fldb1 of ModelB resources having foreign-key-to-same(ModelA) [some (not all) — i.e., not all b_objs need to be modified ]

The update data must be sent as follows :

data = {
    'flda1' : 'PRADEEP 2 title CHANGED',
    'flda2' : 'medium CHANGED again...',
    "b_objs" : [
        {'fldb1':'TB', 'modela':99, 'id':184},
        {'fldb1':'STF', 'modela':99, 'id':185}
    ]
    }

And the query parameter contains id for ModelA
The problem is that the view and the serializer are working properly for flda1 and flda2. But when I add b_objs, I get errors.

Here is my view :

class ViewA(RetrieveUpdateDestroyAPIView):
    queryset = ModelA.objects.all().prefetch_related('b_objs')
    serializer_class = ModelASerializer
def update(self, request, *args, **kwargs):
    modela_id = = request.query_params['id']
    modela_ins = queryset.filter(pk=modela_id).first()
    serializer = self.get_serializer(project, data=request.data, partial=True)
    serializer.is_valid(raise_exception=True)
    serializer.save()

And serializers are :

class ModelBSerializer(serializers.ModelSerializer):
    class Meta :
        model = ModelB
        fields = '__all__'
class ModelASerializer(serializers.ModelSerializer):
    obj_bs = ModelBSerializer(many=True)
    def validate(self, data) :
        # validation code
        return data
    def update(self, instance, validated_data):
        print(validated_data)
        for field, value in validated_data.items():
            setattr(instance, field, value)
        instance.save() # this saves ModelA fields
        return instance

The problem is that validated_data in update does not show id in b_objs that is sent in data
So I am not able to filter ModelB resources from database and make changes to them

How to do