Welcome to MusicBrainz!
... have just created my first new entry (http://musicbrainz.org/release/2f38664e … a0cab5484d). I'm referring to the guidelines with respect to artist role relationships, and I think I've got it right, but I wanted to double check.
I've related the soloist, conductor and orchestra to each individual track, even though they are the same for all the tracks of the release. This is as per the guideline: "If the relationship is applicable to all tracks on a release, apply it to every work or recording on the release". Am I correct?
Yes, you are correct. These relationships logically belong to the recordings because the performers performed the music contained in the recording.
The important practical consequence shows up when you reuse the recording object (eg. in a compilation) - it carries its relationships with it.
I noticed that you linked "The Chamber Orchestra of Europe" performance once as "chamber orchestra" and 3 times as "orchestra". Similarly you linked "Douglas Boyd" performance twice as "oboe" and twice as "solo oboe". I suppose this was not intentional?
Do you know that you can create a relationship for multiple tacks at once? In the release page you click on "Relate to ..." and select "Relate to recordings".
Also it is strongly recommended to add a link to a reliable online information about the edited objects (recording label page, album cover scans, Discogs, Amazon, Allmusic, review etc.) to the edit note so that other editors could vote on your edits.
One last thing :) The classical style guideline has changed recently (finally! :) and now both the composers and performers should be put into the artist field:
I'm comparing this against a CD of mine which is already in the database, and which I believe is incorrect (http://musicbrainz.org/release/b1adb4f7 … 0a1c6c9475). Amongst other issues, Jessye Norman is credited against the release, when she only features on the final track. I would have thought the guidelines suggest that all global relationships (in this case, conductor, orchestra, and, for the final track, soprano soloist) should be applied to the individual tracks?
Yes, the relationships should be at the individual tracks/recordings. If you want you can correct the release by moving the relationships.
Probably the original editor did not know which individual recordings should have which relationship or (s)he was just lazy.
Secondly, I've created my new entry with Mozart and R Strauss as the artists (the composers in this case), rather than as Various Artists. I'm not sure of the subtleties of when to choose.
In http://musicbrainz.org/release/2f38664e … a0cab5484d ?
That is correct. The decision depends on the number of artists. Normally you use Various Artists with compilations and samplers.