Levels in the structure of works

[derobert]

@Sophist

What I am not yet clear about is whether an MB work could be e.g. a Movement of a one main work, and an Act of another - in which case relationship attributes are definitely the way to go. Or is a Movement always a Movement, in which case we need to decide whether we are happy to accept the possibility that in MB it is shown as a Movement in one relationship and an Act in another?

The vast majority of the time, a movement/act/etc. is only associated with one main work; the graph formed by all the related works is a tree.

Exceptions that come to mind:

• Symphony exists in multiple revisions, but the composer only revised the 1st and 4th movements. The 2nd and 3rd are shared between both revisions. In this case, the type (“movement”) is the same.
• Composer takes parts of a ballet or opera and makes a concert/symphonic version of them. Sometimes those are different works (arrangements), but can probably be the exact same thing. Then the type would be different (“scene” or “overture” vs. “movement”). I can’t think of an example at the moment, though—all the ones I can think of are arrangements. Hard to believe it doesn’t exist, though.

It’d be interesting to look for works that are part-of more than one work… but I don’t have a MB database loaded into Postgres anywhere to try and run that query.