Towards a "more declarative" XML query language

Abstract

To extract and restructure information in XML documents, various query languages have been proposed in the past decade. These languages take navigational or pattern-based approach to data extraction and often claim to be declarative. However, declarativeness in them is not as prominent as in SQL because they often exhibit a procedural style in handling heterogeneity and presenting tree-like document structure. In this paper, a new XML query language called XTQ is proposed to address this challenge. XTQ is a pattern-based language which introduces disjunction as well as conjunction operators in composing tree-like patterns named LXT (Logic XML Tree) for data extraction. LXT can expressively handle heterogeneity common in XML queries. Based on a hierarchically structured pattern with considerate restructuring rules, XTQ deploys a flexible hierarchically grouping mechanism in data construction so that complex tree-like structure can be intuitively presented. Examples from common query request show that XTQ can present XML queries more declaratively than existing studies. © 2010 Springer-Verlag.