Make a Django model read-only?

You can override the save method and not call super if you wanted to. That'd be a fairly easy way of accomplishing this.

# blatantly ripped the save from another answer, since I forgot to save original model
def save(self, *args, **kwargs):
    if self.id is None:
        super(ModelName, self).save(*args, **kwargs)

def delete(self, *args, **kwargs):
    return

You should probably also raise an exception if a delete or update is attempting to occur instead of simply returning. You want to signal the user what is happening - that the behaviour isn't valid.