Pramod Sadalage, has written an article on Behaviour Driven DB development. http://www.methodsandtools.com/archive/archive.php?id=78.
He writes about adding behaviour to the domain model and how that behaviour is translates into database objects, with tests. In the project I'm working on, which driven by a Web UI I use the UI behaviour to build the presenter and through this add behaviour to the domain model. It's at the last stage that I add the persistance, through Nhibernate.