The music database is central to the way Giocoso works. It contains listings of what FLAC files exist and where on the hard disk they can be found (but not the FLAC files themselves, of course, as they remain entirely independent, physical files stored on disk).
New in Giocoso Version 3 is the fact that a music database is now compulsory, even if doesn't have any significant data within it. That's because even plays of music sourced directly from the hard disk (see Play Menu option 3) have to be recorded in Giocoso's 'history of plays' table. Accordingly, the very first thing you should do after installing Giocoso is to create a new music database (see Option 1).
Part of the database creation process is to point Giocoso in the direction of your FLAC music files collection: for each FLAC the program discovers, the database will capture and record data extracted from the tag metadata you've (hopefully!) added to your FLACs, such as the composer, the performers, the recording date, the genre and so on. The presence of this metadata within a fairly small database is what makes it possible for Giocoso to randomly select 'all choral works by Haydn that were recorded by Thomas Beecham' (for example): the data is readily accessible and searchable and database randomisation techniques can be applied to it very easily. It's much easier doing it that way than, for example, having to freshly analyse every FLAC every time you think you might want to play it!
This means, however, that after once creating the music database, you need to keep its contents up-to-date. If you acquire 15 new CDs, rip them and add them to your collection, you'd better tell Giocoso about that: the program cannot select to play that which it doesn't know to exist, after all.
The music database is used, too, every time a recording plays: Giocoso records the fact of a completed 'play' in its database, along with the associated metadata for that recording. In this way, a history of your plays is built up over time. A play history can be a mere curiosity (as in, 'wow: I didn't realise the last time I played Adolphe Adam was over a year-and-a-half ago'); it can also be useful, in the sense of 'play me choral music by Haydn conducted by Beecham that I've never played before'. Without a play history to scan, that last clause of your requirements cannot be answered.
Being able to create, protect, query and refresh the music database is thus a core Giocoso function: and the Database Management menu is how you go about doing all those things.
Links to a detailed description of each menu option are listed below: