Multiversion views: Constructing views in a multiversion database

Commercial DBMS offer mechanisms for views and for versions. Research and d evelopment efforts in these directions are, however, characterized by conce ntration on either the one or the other mechanism, very seldom trying to ta ke advantage of their complementary properties. This paper presents the mul tiversion view mechanism, which allows these orthogonal concepts to be mana ged together, taking advantage of their combined characteristics. Unlike pr evious efforts to combine views and versions, multiversion views create vie ws over versions of data, thereby offering users coherent logical units of the versioned world. They allow a wide range of (virtual) data reorganizati on possibilities, which encompass, among others, operations found in tempor al databases and CLAP. Multiversion views are illustrated and motivated by needs from a real life large case study of complex configuration management , described at the end of the paper. (C) 2000 Elsevier Science B.V. All rig hts reserved.