Move a python / django object from a parent model to a child (subclass)

Question

I am subclassing an existing model. I want many of the members of the parent class to now, instead, be members of the child class.

For example, I have a model Swallow. Now, I am making EuropeanSwallow(Swallow) and AfricanSwallow(Swallow). I want to take some but not all Swallow objects make them either EuropeanSwallow or AfricanSwallow, depending on whether they are migratory.

How can I move them?

Answer 1

It's a bit of a hack, but this works:

swallow = Swallow.objects.get(id=1)
swallow.__class__ = AfricanSwallow
# set any required AfricanSwallow fields here
swallow.save()

Answer 2

I suggest using django-model-utils's InheritanceCastModel. This is one implementation I like. You can find many more in djangosnippets and some blogs, but after going trough them all I chose this one. Hope it helps.