I believe Tony was talking about the data from AllMusic. For compilations it doesn't include the name of the artist (at least for the few albums I pulled up over the past week). What it does include are the names of the composers/writers/lyricists (credit) for the tracks.

Exactly. So I understand why T&R doesn't put them in.

In those cases I always enter the original performer names from the liner notes. I just wish there was some database which did this for me automatically. Allmusic comes the closest, but it's not quite there, still.