VERSION
A performance is a version of a work performed by one or more performing artists.
Example: Abbie Mitchell recorded a version of the work Summertime on July 19, 1935. This performance, also titled Summertime , was released in 1974 on George Gershwin Conducts Excerpts from Porgy and Bess.
UNIQUENESS
A performance refers to 1 specific rendition of a work. (R)
Consequence: If ArtistA recorded WorkW, a first time for a movie, and a second time for an album, then 1 performance in the database can't refer to both recordings. Or put differently: If a performance in a movie is not the same as the one on the soundtrack release, then they can't be the same performance entry.
VIRTUAL DUET
A special case: of a performance : Virtual duet
A performance presented like a duet (=joint performance), but where one of the artists was sampled and didn't actually co-perform.
Example: Cold Heart by Dua Lipa - Elton John [sampled]
Example : Your Precious Love by Sarah Connor with Marvin Gaye [sampled]