Project

  - Introduction

  - Objectives

  - Documentation

  - User Guide
  - Use Case

  - About

  Download

  - Application

  - Applet

Introduction

The prevalence of XML has driven the need for a query language that appeals to a wide group of users including those with minimal or no programming skills.  Two textual languages XSLT [3] and XQuery [4] are provided by the W3C (World Wide Consortium) to express XML document transformation and to query XML data. However, these languages are too complex for users, who might only be equipped with the basic data model of XML which should be adequate for users to perform simple queries and transformation.

Therefore, a graphical query language can be potentially helpful whereby users do not need to remember the syntax of a textual of a language, all they need is to select options and draw diagrams. With this group of users in mind, two projects XQBE (Xquery by Example) [1] and GXQL (Graphical XQuery Language) [2] was developed, the former defines many abstract symbols e.g.,  trapezoids, circles of different colors to express queries. However, it is difficult to remember the representation and concept of each abstract symbol. Secondly, the tree-mapped representation is complicated and not visually obvious to first-time and occasional users. Thirdly, any extension to XQBE would require more abstract symbols, edges and labels which would make the representation even harder to understand and use.

This software aims to be more intuitive than both XQBE and GXQL by introducing fewer symbols and a visually obvious association between the query and its output. In addition, we do not attempt to represent the entire XQuery syntax visually and support a subset of XQuery syntax only.

1. D.Branga, A. Campi, and S. Ceri. (XQuery by example): a visual interface to the standard XML query language. Trans. On Database Systems (TODS)
2. Zheng Qin, Benjamin Bin Yao, Yingbin Liu, and Michael McCool. A Graphical Xquery Language Using Nested Windows.
3. W3C. Extensible Stylesheet Language (XSL). http://www.w3c.org/TR/xsl/, October 2001.
4. W3C. XQuery: An XML Query Language. http://www.w3.org/XML/Query, November 2002.