| As information published in the form of XML-compliant documents speedily mount up, efficient and effective query processing and optimization for XML have now become extremely important than ever.; During the past few years, a large amount of work has been devoted to XML data management, and more recently, much work on XML query processing and optimization has been reported. However, although there is great consensus on XQuery as a standard query language, there is to date no accepted "XML query algebra", nor a complete comprehensive methodology for XML query processing and optimization. This thesis reports our recent advances in the effort made for XML structured-document query processing and optimization.; We propose DUMAX---a Dual Mode Algebra---in an effort to provide a complete algebra for XML query representation and optimization; wherein operators work in two modes: shallow (node) or deep (tree). As an integral part, query equivalences and optimization rules are investigated as well. |
