Complex object retrieval via structural join index hierarchy mechanisms: evaluation and selection approaches

In this paper, we introduce structural join index hierarchy (SJIH) mechanisms that mimic the class composition hierarchy of the complex objects to provide direct access to complex objects and/or their component objects. SJIH extends the work on join index hierarchies by providing efficient and flexible access to complex objects, thus unifying various previous indexing methods proposed for object oriented database (OODB). A cost model for processing the queries and maintaining the indices is developed. A heuristic algorithm is designed to select appropriate indices to efficiently process a given set of queries. We show that SJIH indexing mechanisms facilitate efficient retrieval of complex objects. Given a set of queries and a limited index storage space, the heuristic algorithm facilitates fast selection of near-optimal set of indices for efficiently executing the queries