A foundation for evolution from relational to object databases

Abstract

Object models have an important part to play in the future of database systems, but progress is hampered by lack of agreement on their essential characteristics. Strong constraints on the design of a common model are exercised by the need to interface well with object models in programming languages, and the desirability of a smooth evolution from existing database technology. This paper briefly reviews some salient features of database and language object concepts, and then draws attention to a correspondence between relational and object database models. It shows how this can be exploited in defining Object SQL (OSQL), which reinterprets and extends SQL to define object types and instances, together with functions which relate and manipulate objects. OSQL has been implemented as an interface to the Iris Object DBMS.