Databases and Information Systems

Kazimierz Subieta and Jacek Plodzien Polish-I apanese Institute of Information Technology & Institute of Computer Science PAS, Warsaw, Poland E-mail: {subieta,jpl}@ ipipan.waw.pl We attempt to widen the scope in which object views are typically set, following the paradigms of programming languages rather than traditional database concepts, such as relational/object algebras or calculi. A well-known environment stack is used as a semantic basis for definitions of query operators. In this setting naming, scoping and binding are central issues and a virtual (non-materialised) database view is a stored function. A function output is a structure built upon atomic values, references and names. Such functions perfectly simulate virtual objects and virtual classes. The approach can be coupled with the query modification technique based on macro-substitution. It significantly reduces performance problems related to processing views. The approach is relevant to object query languages such as OQL.