I’ve used vux’s sqlite nodes and the SQLite Manager addon for Firefox before and found them to be really nice to use. Also, it only needs a single local file for the database and therefore handles more like a csv.
Really, sqlite sounds perfect for that.
You don’t need to run a server and you can have a single table for each category. Also being able to access the data with sql queries is way nicer than the sift/sort/select/+ etc node hydra, a csv would probably lead to.
I agree with@skern, you may also try XML (not the best thing but easier to construct and understand maybe, I still prefer mysql for database handling but there is no reason to mess with local servers and stuff)