XTree for Declarative XML Querying

摘要

How to query XML documents to extract and restructure the information is an important issue in XML research. Currently, XQuery based on XPath is the most promising standard of W3C. In this paper, we introduce a new set of syntax rules called XTree, which is a generalization of XPath. XTree has a tree structure, and a user can bind multiple variables in one XTree expression. It explicitly identifies list-valued variables, and defines some natural built-in functions to manipulate them. XTree expression can also be used in the result construction part of a query, to make it easy to read and comprehend. With these differences, XTree expressions are much more compact, and more convenient to write and understand than XPath expressions. We also give algorithms to convert queries based on XTree expressions to standard XQuery queries.