Hello Rainer,
so far, the Musipedia collection is a collection of themes and melodies. Thus, one should create multiple entries for the same song if it contains multiple themes.
I am planning to improve the database scheme so that one could indicate which themes belong to the same piece, which would be useful to avoid the duplication of information or inconsistencies. I am not quite sure yet what the best structure would be, and how it could be incorporated in the user interface without making it more clunky and complicated than it already is.
We would probably need a table of works with fields such as lyrics, title, composer, link to free sheet music etc., and another table of themes with fields such as Lilypond or abc code, Parsons code, MIDI file, sheet music bitmap etc.
Then there would be an n-to-1 relationship between themes and works.
So far, so good. But one would also need an easy way of picking an already existing "work" entry when adding a new "theme" from the same work, or, if that does not exist yet, an easy way of creating them both at once.
Anyways, for now I would suggest to just enter multiple themes, even from the same piece, as separate entries, and to duplicate the metadata (composer, title, etc). Once the database structure is improved, those entries will have to be linked together, but we already have that problem anyways with existing entries.
Cheers,
Rainer