Combining Indexing Technique with Path Dictionary for Nested Object Queries
Wang-Chien Lee, Dik Lun Lee · 1995
A path dictionary encodes the connections among objects in the aggregation hierarchy. It has been shown to be an efficient mechanism for supporting nested object queries [6]. In this paper, we present a new method, called the path dictionary index method, which combines indexing techniques with the path dictionary method. We describe the operations of the new mechanism and develop cost models for its storage overhead and query and update costs. Finally, we compare the new mechanism to the path index method [3]. The result shows that the path dictionary index method is significantly better than the path index method over a wide range of parameters. 1 Introduction The concept of class allows object-oriented database systems (OODBSs) to model complex data more precisely and conveniently than the relational data model. A class may consist of simple attributes (e.g., of domain integer or string) and complex attributes with user-defined classes as their domains. Since a class C may have a ...