An incremental mechanism for schema evolution in engineering domains

The authors focus on one class of schema revisions necessitated by a very basic phenomenon: a given individual object evolves into a family of objects which are similar to it in many ways. This is commonly called the version problem. In theoretical terms, one can handle the above schema change in the standard, object-oriented database models by the interposition of suitable abstractions into the existing type lattice. There are practical and engineering difficulties with such schema changes. The authors propose an incremental mechanism called instance inheritance which is well suited to handling the schema changes without the attendant practical costs. The authors formally characterize this augmentation to the standard database models, and show examples of its applications