3. How to allow creating only one object from the admin?

The UMSRA admin has asked you to limit the number of categories to only one. They want every entity to be of the same category.

You can do this by:


def has_add_permission(self, request):
    if self.model.objects.count() >= MAX_OBJECTS:
        return False
    return super().has_add_permission(request)

This would hide the add buton as soon as one object is created. You can set MAX_OBJECTS to any value to ensure that larger number of objects can’t be ceated than MAX_OBJECTS.