A decision procedure for XPath satisfiability in the presence of DTD containing choice

  • Authors:

  • Yu Zhang;Yihua Cao;Xunhao Li

  • Affiliations:

  • Department of Computer Science & Technology, University of Science & Technology of China, Hefei, China and Anhui Province Key Lab of Software in Computing and Communication, Hefei, China;Department of Computer Science & Technology, University of Science & Technology of China, Hefei, China;Department of Computer Science & Technology, University of Science & Technology of China, Hefei, China

  • Venue:
  • APWeb'08 Proceedings of the 10th Asia-Pacific web conference on Progress in WWW research and development
  • Year:
  • 2008

Quantified Score

Hi-index 0.00

Visualization

Abstract

XPath satisfiability is one of the most basic problems of XML query optimization. A satisfiability decision framework, named SAT-DTD, is proposed to determine, given a set of XPath queries P and a DTD τ, which subset of P are satisfiable by an XML tree conforming to DTD τ. In the framework, an indexed NFA is constructed from the set of XPath queries P, and then the NFA is driven by simple API for DTD (SAD, something like SAX) events, derived from DTD τ, to evaluate the predicates in P and to decide the satisfiability of P. Especially, DTD choice (i.e. '|' operator) is taken into consideration, and an algorithm, named SAT-DTD_C, which bases on SAT-DTD, is put forward to determine the unsatisfiability caused by DTD choice. At last, the complexity of the algorithms is analyzed, and the correctness of the algorithms is tested by experiments.