XML is the next big thing in the world of databases!

What is XQuery?

As defined by the WorldWide Consortium(W3C) "XML is a versatile markup language, capable of labeling the information content of diverse data sources including structured and semi-structured documents, relational databases, and object repositories. A query language that uses the structure of XML intelligently can express queries across all these kinds of data, whether physically stored in XML or viewed as XML via middleware."

Understanding this growing need of database developers, XML Query Working Group and XSL Working Group have jointly released the first version of XQuery, a query language that is broadly applicable across many types of XML data sources. It uses queries to extract data from Web documents enabling XML files to be accessed as databases.

The language currently is in the 'last call' status at W3C, the consortium is working on the comments received from the community.

What products are in line?

IBM and Microsoft have created a test suite that can be used by application developers to query XML files using XQuery, this suite was presented to W3C last year. Not only IBM and MS but also software makers like BEA and Oracle have already started integrating XQuery in their products.

According to Pat Selinger, IBM fellow and vice president of data management architecture and technology 'XML is the next big thing in the world of databases.' IBM is using XQuery to bundle XML with its database software for data integration (the project was formerly known as Xperanto.)

As an experiment IBM used XQuery in a prototype database to integrate commands to show the use of Web services for distributed data sources. IBM's DB2 Information Integrator uses XQuery and can be used by businesses to integrate and search the repositories and formats of information as if they were a single database. The DB2 Information Integrator is also compatible with third party databases like Sybase, Oracle, SQL Server, Terradata etc.

According to Selinger IBM's mission is to make DB2 a database software with 'two front doors' namely SQL and XQuery. This will enable database developers to use each of these languages to access data, which may be stored relationally or as an XML.

Viewpoints...

Jeff Jones, director of strategy, data management at IBM, is of the opinion that XQuery is a very powerful way to handle XML content as it offers power to manipulate, browse, search integrate, and aggregate data. Since the language has inherited from SQL it will be easy for the database vendors to incorporate it into their line of products. Software developers can query XML- tagged information in databases using proprietary code.

Inspite of the fact that this query language has its roots in SQL there are differences, as well commented Stephen O'Grady, senior analyst with research firm Redmonk. According to O'Grady 'SQL is declarative, while XQuery is semi-procedural' and a programmer has to acquire the relevant skill sets to use it. O'Grady feels that since there is a learning curve attached with the language developers should make proper use of the available test-suites to make themselves comfortable with the technology and its implications.

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