Consistency of versions in objects-oriented databases

This paper presents an approach to maintaining consistency of object versions in multiversion database systems. In this approach a multiversion database is considered to be a set of logically independent and identifiable database versions. Each database version is composed of a version of each object stored in the system. However, identical object versions may be shared by many database versions. Database versions are identified by version stamps. Version stamps are also used to associate object versions with database versions. Because of the particular construction and semantics of version stamps, object version management is very efficient. Moreover, it is orthogonal to other problems of version management, such as object addressing, concurrency control, access authorization, etc. The paper explains how the requests of object reading, updating, creating and deleting are realized.