Reduce, Reuse, Recycle: Practical Approaches to Schema Integration, Evolution and Versioning

Three themes are apparent in recent schema integration, evolution and versioning research. First, the need to reduce the number of schema changes that are necessary. The approach here has been to build into the conceptual and data models the scope to accommodate modest changes to definition. Second, research that aims to reuse the current schema definition through procedures that mask the changes through sophisticated wrappers or techniques for multiple extensional data. Finally, techniques that enable schema change to be accommodated as seamlessly and as painlessly as possible. All these approaches have their limitations and strengths. This paper investigates each of these approaches and outlines the current research directions in schema integration, evolution and versioning.