Can a model be more than just a database layer?

[eluser]GSV Sleeper Service[/eluser]
if you want to use an object with db->update, then yes, you will have to make a separate object. from what I understand, codeigniter models are intended to be used as a place to keep your i/o stuff, you're trying to use them almost like an ORM.

you might want to take a look at Doctrine - http://www.doctrine-project.org/ , which can automatically create objects that match your DB.