An object model at conceptual level to support updatable views on object-oriented databases

Abstract

The research on view mechanisms for object-oriented databases can be classified into two independent issues, languages to define views and the underlying object models. This paper presents an object model at the conceptual level of abstraction. We call it the view class and real-world object model (V-R model). The major goal of the V-R model is intended to support updatable views efficiently for the object-oriented database systems. The V-R model elaborates a special method to describe the instance-of relationship between stored objects and classes so that a stored object can be the instance of several classes simultaneously. Query results and views can be managed like classes without creating temporary objects or tuples since the V-R model is closed against query operations. In this way, updates on views can be supported easily. This paper also explores the update semantics in depth. By utilizing the specialty of the V-R model, a more eligible update translation is proposed for the updates on classes with or without inheritance relationships and for the updates on views. To show that the V-R model is not only theoretical, how to implement the V-R model and how to integrate the V-R model into an object-oriented database system are illustrated. (C) Elsevier Science Inc. 1996