Description
This article reports the result of the author’s recent work on XML query processing/optimization, which is a very important issue in XML data management. In this work, in order to more effectively and efficiently handle XML queries involving pure and/or negated containments, a previously proposed deterministic optimization approach is largely adapted. This approach resorts to heuristic-based deterministic transformations on algebraic query expressions in order to achieve the best possible optimization efficiency. Specialized transformation rules are thus developed, and efficient implementation algorithms for pure and negated containments are presented as well. Experimental study confirms the validity and effectiveness of the presented approach and algorithms in processing of XML queries involving pure and/or negated containments.