Querying and restructuring XML data by graphical query language

Abstract

PurposeThe rapid development of Extensible Markup Language (XML) from a mere data exchange format to a universal syntax for encoding domain specific information increases the need of new query languages specifically visualized to address the characteristics of XML. Such languages should be able not only to extract information from XML documents, but also to apply powerful restructuring operators, based on a well‐defined semantics. Moreover, XML queries should be natural to write and understand, as also end‐users are expected to access the large XML information bases supporting their businesses. The purpose of this paper is to propose a new graphical query language for XML (GQLX) for querying and restructuring XML data.Design/methodology/approachThe methodology emphasizes on GQLX's development, which is based on G‐XML data model syntax to express a wide variety of XML queries, ranging from simple selection to expressive data transformations involving grouping, aggregation and sorting. GQLX has an operational semantics based on the annotated XML, which serves to express queries and data trees in the form of XML. The paper also presents an algorithm to achieve the matching between data and query trees after translating them into annotated XML.FindingsDeveloped and demonstrated were: a G‐XML syntax; annotated XML for the semantic operations and a matching algorithm.Research limitations/implicationsThe future research work on this language lies in expanding it to include recursion and nested queries.Practical implicationsThe algorithms/approaches proposed can be implemented to enhance the performance of the XML query language.Originality/valueThe proposed work integrates various novel techniques for XML query syntax/semantic into a single language with a suitable matching algorithm.