Despite a large body of work on xml query processing in relational environment, systematic study of not -twig queries has received little attention in the literature. Such queries contain not-predicates and are useful for many real-world applications. In this paper, we present an efficient strategy to evaluate not-twig queries on top of a dewey-based tree-unaware system called Sucxent++ [11]. We extend the encoding scheme of Sucxent++ by adding two new labels, namely AncestorValue and AncestorDeweyGroup, that enable us to directly filter out elements satisfying a not-predicate by comparing their ancestor group identifiers. In this approach, a set of elements under the same common ancestor at a specific level in the xml tree is assigned same ancestor group identifier. Based on this encoding scheme, we propose a novel sql translation algorithm for not-twig query evaluation. Real and synthetic datasets are employed to demonstrate the superiority of our approach over industrial-strength rdbms and native xml databases. © 2011 Springer-Verlag.
CITATION STYLE
Soh, K. H., & Bhowmick, S. S. (2011). Efficient evaluation of NOT-twig queries in tree-unaware relational databases. In Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) (Vol. 6587 LNCS, pp. 511–527). https://doi.org/10.1007/978-3-642-20149-3_37
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