A database evolution approach for object-oriented databases

The paper describes a composite evolution approach which integrates the evolution of the various types of entities in an object-oriented database into one model. The approach provides maintainers with a coherent and comprehensible view of the system and at the same time maintains change histories at a fine granularity. Links among meta-objects are implemented using dynamic relationships which are semantic constructs and first-class objects. Referential integrity is maintained by the relationships architecture reducing the evolution complexity at the meta-object level. A customisable and exchangeable instance adaptation approach is proposed. The approach is based on separating the instance adaptation code from class versions using aspects, abstractions used in Aspect-Oriented Programming to localise crosscutting concerns. A high level object-oriented model offering transparent access to the proposed evolution functionality is provided.