The rise in prominence of Service Oriented Architectures (SOA) has triggered a storm of debates on how best to build enterprise SOA-based applications and establish a predominant industry position. In the meantime, the W3C XQuery language is accelerating toward "Recommendation" status; although comparatively little time has been spent debating XQuery-s role in SOA, I expect that its rising prominence will soon capture the attention of many Java developers seeking to build enterprise SOA-based applications.

The W3C XQuery specification provides a native XML query language that integration platforms and components can use to aggregate data under the unifying umbrella of XML. XQuery levels the data integration playing field by providing a single interface that lets developers access multiple data sources under a unifying data model.

Why is XQuery so important? In talking with many customers building SOA applications, I have found that one of their greatest challenges lies with data integration. Business-critical data is typically stored in relational database management systems (RDBMSs), providing reliable and centrally managed data repositories. In spite of the dominant position of relational data, the growth of XML (especially as a format for exchanging data over the Internet) has forced business applications to function seamlessly with both XML and relational data.

Fortunately, W3C XQuery has emerged as an indispensable approach for integrating data, in particular when working with XML and relational data. To that end, I believe developers will increasingly rely on XQuery technology that has the ability to abstract any data source as XML, lets them work with XML and relational data together in a highly optimized fashion, and reduces the effort of building applications suited to the demands of SOA.

For example, we are already seeing the major RDBMS vendors embedding XQuery support as a means to exposing relational data as XML data sources, therefore implicitly increasing data portability and accessibility via XQuery. RDBMSs without integrated support for XQuery will continue to delegate the responsibility to the middle tier to ensure their equal participation in increased data integration. In fact, I believe it is likely that the middle tier will emerge as the sweet spot for Java developers to establish an integration component end-point (iCE) as a means to integrate a set of distributed data sources. In this scenario, technologies like DataDirect XQuery from DataDirect Technologies will let developers weave together distributed relational data sources with XML data and expedite the migration toward SOA-based applications.

For those groaning at the prospect of yet another query language, the power of XQuery and the productivity gains of using XQuery for data aggregation amplify how XQuery can work in concert with business applications evolving toward SOA. Significantly, XML IDEs already provide extensive tools to help developers build and migrate their Java applications to use XQuery, thus maximizing their business data for SOA.

XQuery uniquely safeguards corporate investment in relational databases, while enabling established data for participating in your enterprise-s SOA push. As the power of the XQuery language becomes more fully appreciated, I expect the importance of middle-tier XQuery implementations will result in significant productivity gains for Java developers building and deploying applications.