I think before we get into interview questions, it would be much better to define what a DBA/Developer needs to be, know, and do.

I remember a post that someone made several years ago that pretty well had it down pat. I was going to add it to my briefcase but I apparently forgot. IIRC, the post was about job descriptions and what was posted in one of the posts on that thread was just brilliant. I wish I could find it again.