Django model inheritance: create sub-instance of existing instance (downcast)?

Question

I\'m trying to integrate a 3rd party Django app that made the unfortunate decision to inherit from django.contrib.auth.models.User, which is a big no-no for plu

Answer 1

@guetti's answer worked for me with little update => The key was parent_ptr

parent_object = parent_model.objects.get(pk=parent_id)  
new_child_object_with_existing_parent = Child(parent_ptr=parent, child_filed1='Nothing')
new_child_object_with_existing_parent.save()

I wanted to create entry in my profile model for existing user, my model was like

from django.contrib.auth.models import User as user_model
class Profile(user_model):
     bio = models.CharField(maxlength=1000)
     another_filed = models.CharField(maxlength=1000, null=True, blank=True)

At some place I needed to create profile if not exists for existing user so I did it like following,

The example that worked for me

from meetings.user import Profile
from django.contrib.auth.models import User as user_model

user_object = user_model.objects.get(pk=3)  
profile_object = Profile(user_ptr=user_object, bio='some')
profile_object.save()