Optimization of queries using nested indices

Abstract

The notion of nested object is a basic concept of the object-oriented paradigm. It allows the value of an object attribute to be another object or a set of other objects. This means that a class consists of a set of attributes, and the values of the attributes are objects that belong to other classes; that is, the definition of a class forms a hierarchy of classes. All attributes of the nested classes are nested attributes of the root of the hierarchy. In a previous paper [Bert 89], we have introduced the notion of nested index that associates the values of a nested attribute with the objects instances of the root of the hierarchy. In that paper, we have evaluated the performance of this indexing mechanism in the case of queries containing a single predicate. In the present paper, we consider the usage of nested indices in the framework of more general queries containing several predicates.

This work was partially performed while the author was visiting the Microelectronics and Computer Technology Corporation, Austin (Texas)