Yes.
There are two types of database you can access to either store simple name/value pairs in or manually create tables and store more complex data
Modding.OpenSaveData() gets you access to a per-game db
Modding.OpenUserData(sModName, iModVersion) gets you access to a db that persists between games (useful for storing user configuration preferences)
The latest version of ModBuddy implies that you can add data to (at least) one of these databases via the standard OnModActivated -> UpdateDatabase mechanism (but I've not experimented tp work out which, if indeed it workd at all)
HTH
W