Can Django models use MySQL functions?

Question

Is there a way to force Django models to pass a field to a MySQL function every time the model data is read or loaded? To clarify what I mean in SQL, I want the Django model to

Answer 1

Using Django signals you can do stuff when a model instance is saved, but as far as I know you can't trigger anything on read.

EDIT: My bad, it seems you can do stuff when initializing a model instance.