Since an object-oriented database system (OODBS) dealing with composite objects requires expensive traversal costs to process user queries, query processing and indexing have become important issues in the success of object-oriented database systems. In this paper, we propose a new signature-based indexing scheme entitled c-signature. The c-signatures are abstracted from objects in a path in concatenation and are stored in a class-oriented way, so as to reduce search space. By positioning the c-signature file before the path dictionary, we can avoid expensive scanning of the database. Also, the c-signatures pointing to an s-expression in the path dictionary make it possible to avoid the sequential scanning of the path dictionary. Based on the proposed scheme, we develop implement the c-signature and its competitors such as path index, path signature, path dictionary, class unit signature, path dictionary index, and s-signature schemes. Using the experimental results, we compare the c-signature with the competitors under different degrees of reference sharing and in terms of the page I/Os of each scheme. Finally, we show that our c-signature scheme achieves significant improvements in the retrieval operation.
CITATION STYLE
Shin, H., & Chang, J. (1999). Combining c-signature with path dictionary for query processing of nested objects in OODBS. In Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) (Vol. 1677, pp. 312–321). Springer Verlag. https://doi.org/10.1007/3-540-48309-8_29
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