Fixing a bad schema
Connection between the old and new schemas
project(BadAlbum, [artist, artist_website]) → Artist
project(BadAlbum, [artist, title, year, label, label_website]) → LessBadAlbum
BadAlbum == join(LessBadAlbum, Artist)
- We have decomposed BadAlbum to Artist and LessBadAlbum.
- The decomposition is done using a join which is lossless: Table = join of projections
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