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W3C Issues Latest XQuery Draft 1.0 Standard

by Vance McCarthy

Tags: XQuery, SQL, XML, Standard, Query, Developers, Test Suite,

Late last week, the W3C released a working draft for an XQuery 1.0 standard. The release of the document marks the latest steps among a variety of software vendors -- application, database and tools -- to agree on a common standard for querying XML data and documents. The latest draft, which follows the submission of an XQuery test suite co-developed by Microsoft and IBM, also reflects collaboration with technicians from Oracle, BEA, Bell Labs and others.

For all the recent disharmony among database providers over the topic of web services workflow (or choreography), the latest draft demonstrates signs of unity among app and SQL database vendors on several fronts.

Case in point: The W3C continues to review a test suite for XQuery, the web services standard for querying XML data and documents.

XQuery is the proposed way for working with unstructured, non-relational data, and likely follow-on to relational data that uses SQL The standard also will lay out core specifications for bridging the two data worlds. Even though the test suite being submitted is based on work done jointly by IBM and Microsoft, database competitors Oracle, Informix, and datamining software provider Business Intelligence have all publicly supported the XQuery work.

The aim of the test suite is to provide W3C with a mechanism to make sure that different vendors' XQuery implementations are alike enough to allow developers to work with XQuery across multiple database platforms. Once the test suite is submitted, the W3C will put it through internal testing for compliance to the proposed XQuery specs, and then put the test suite out to public comment before making it part of the final proposed standards package. A full XQuery standard could be completed by yearend, with full ratification (the W3C's Last Call) possible by Q1 2004.
In the meantime, just about every SQL vendor is making public commitments to support XQuery, whenever it's final. For it's part, IBM has stated that once XQuery becomes a final standard, it will be added to its DB2 database line. IBM has released XML for Tables, a language translator that demonstrates how the XQuery interface can be used to access structured data and present it in XML form. Even J2EE app sever vendor BEA Systems is shipping its Liquid Data data access and aggregation product for WebLogic.
Microsoft has also committed to support XQuery in a future version SQL Server. In the meantime, Microsoft is already taking steps to help make current SQL Server 2000 developers more at ease with integrating their data with web pages and XML. For instance, SQL Server 2000's XML query features and XSL stylesheets let Web servers running Internet Information Server (IIS) 5.0 stream formatted query resultsets to browsers in vanilla HTML, according to an SQL Server 2000 review in Visual Studio Magazine by Roger Jennings.

Even as the standard for an XML-based query winds its way to completion at W3C, a core group of SQL devotees openly question just how much XQuery will impact their structured query-based development. At the same time, a growing number of enterprise developers with broad user constituencies -- cross departmental users, suppliers, partners and even customers -- are becoming increasing interested in using non-structured technologies to broaden the availability of their database assets without the need to code and maintain custom clients or application-specific APIs.

Integration Developer News wants to hear from readers who are working on projects designed to "bridge" structured SQL and non-structured XML data assets. Do you have the tools, the standards, the vendor support you need? We'd like to hear your views. Ping us at editor@idevnews.com..


More on XQuery-Related Topics

Wrox' book on implementing XQuery, Early Adopter XQuery, gives newbies the grand tour on the topic, providing easy-to-follow introductions to the XQuery language for those already familiar with SQL and XSLT that others can follow too and a look at the early implementations of XQuery that exist around the internet. In particular, the book looks at .NET and Java classes for incorporating XQuery into your own work and a basic case study demonstrating how to build your own XQuery engine. There's even a look at XQuery;s history and development to date, and what changes might occur in the future before it is ratified.

Microsoft has an XQuery Language Demo site, where devs can obtain a set of downloadable class libraries consisting of managed classes that can be programmed with the 1.0 and 1.1 releases of the .NET frameworks SDK. There is also an online demo page which allows devs to sample XQuery without the need to download the class libraries. Just type in a query, press a button and get the result.

Software AG's Tamino XQuery demo application is a real estate locator web application which lets you search for properties. A simple XML application like this can be built very easily. Take a look at Tamino X-Application and you will be surprised, how easy and convenient it is to develop XML applications based on Tamino. It takes just 5 steps: (1) Define a W3C Schema / DTD; (2) Create & Store XML documents; (3) Transform with XSLT Stylesheets; (4) Query documents with X-Query; and (5) Update documents via http.

xmlhack has links to Fatdog's XQuery engine, the free eval copy, as well as a sample query. The site notes: " The good news is that with the exception of expression lists, FLWRs (for, let where, and return expressions) can be explored in almost full recursive generality, and the features that are in place can be employed against actual data."

Roger Jennings notes that "XML Query Language will soon become the 'SQL for XML' in his overview of Microsoft's Xml.XQuery classes for SQL Server. First published at DevX late last summer, the article is still insightful for putting the current IBM/Microsoft proposed XQuery test suites, just submitted to W3C, into a day-to-day context for developers.

The W3C has issued a Candidate Recommendation of its "DOM Level 3 XPath" proposal, which will map between Document Object Model and XPath to let them better work together. A final review period of the proposed recommendation is now open, with comments due by 26 May 2003. Submit comments to the public mailing list.

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