Django snippets

def clear_nullable_related(self):
    """
    Recursively clears any nullable foreign key fields on related objects.
    This simulates ON DELETE SET NULL behavior manually.
    """
    for related in self._meta.get_all_related_objects():
        accessor = related.get_accessor_name()
        related_set = getattr(self, accessor)

        if related.field.null:
            related_set.clear()
        else:
            for related_object in related_set.all():
                related_object.clear_nullable_related()