What is Versioning-by-Difference

Schema evolution is an important research topic with an extensive literature built up over the years. However, databases are still reluctant to change and thus their evolution is difficult to achieve because the evolution of the schema involves several issues at different levels of the database schema such as the change management at the logical level. Several approaches have been proposed to achieve the evolution of a schema of a wide range of types of databases. Versioning, modification and views are examples of these chosen approaches. In this paper, we present and discuss one of these approaches, which is the versioning approach for database evolution. The future trends of the versioning are presented as well.