Version control and databases

We have a practice of having a branch for each story in the sprint. This works fine with most stories, but what happens when we have stories that affect the database. I found this discussion on the topic which has some interesting reflections and comments. In general, though, my sense is that version control for databases is at best ad hoc and kludgy. RIght now we're doing something similar to Rails migrations, but handled manually. I'd like to formalize that process. I'm looking at DBIx::Migration::Directories, although I find no commentary on it at all, anywhere.