XQuery heating up
At XML 2006 this week, there was a lot of attention given to XML Queryor XQuery. The W3C XQuery specifications are now Proposed Recommendations and there are a numberof implementations available. One of those is included in DB2 9,part of the pureXML feature which adds native XML support to theserver. In earlier versions, XML could be stored in relationaltables by being "shredded" into columns or stored as Character LargeObject (CLOB) or Binary Large Object (BLOB). In DB2 9, XMLdocuments are stored in their native form and can be directlymanipulated. In supporting native XML DB2 introduced support forXQuery.
XQuery is a very powerful query language that can do more than justquery XML data. It can perform transforms and introduce new XMLelements to the output, much like XSLT. In fact, some adventurousdevelopers have used it as a stand-alone programming language. Itemploys XPath expressions to address XML structures and supports the"For, Let, Where, Order, Return" (FLWOR) style. As more andmore data is stored in XML documents, the need for storing them in anXML database is being recognized. This is what I heard from manypeople at the conference and what we have heard from companies in avariety of industries. The combination of an XML database like DB2 9, and the XQuery language will be very powerful and open the door tonew ways of processing and deriving value from XML.
I know that some people had given up on XQuery due to its extremelylong gestation period in the W3C. But, now it is time to takeanother look. That is what many going away from the conferencedecided to do.
Here are some places to get started.
An introduction to XQuery
DebunkingXQuery myths and misunderstandings