Beyond Database Schema Evolution

This paper presents the definition of a new schema model called FDB (Framework DataBase). In modem database environments, there is a need for continuous evolution of database schemas, in order to reflect the changes that happen in the real world. The relational model permits this only through schema modification, which usually leads to time-consuming reorganization of data. On the other hand, schema evolution is supported by the object-oriented model but the commercial systems based on it present certain limitations. especially when a database is already "occupied" with data. The proposed model aims to cover the needs of dynamically evolving database environments and presents an important advantage, compared to the traditional database models: the use of FDB structures give rise to a universal logical schema, which can host any conceptual schema. In practice, this means dynamic definition and modification of entities and their corresponding attributes, without any changes in the schema structure.