Blue Titan Software Inc., San Francisco, and BEA Systems Inc., San Jose, Calif., this week disclosed a joint product marketing effort that officials at the two firms said calls for the vendors to combine XQuery technology with service-level controls.

The W3C is finalizing the XQuery specification, aiming for a final release in late 2002. XQuery is a powerful and convenient language designed for processing XML data. That means not only files in XML format, but also other data including databases whose structure -- nested, named trees with attributes -- is similar to XML.

In my recent XML.com article, Introduction to Native XML Databases, I provided a general overview of native XML databases and what they might be good for. In this article we'll take a look at a native XML database implementation, the open source dbXML Core.

After a brief discussion of grammars, parsers, and BNF, this article introduces JavaCC, a popular parser generator tool. You'll develop sample code that uses JavaCC to build a custom parser, starting from a BNF description of the grammar. Part 2 goes on to show how to use an auxilliary tool, JJTree, to build a parse tree representation of the same parse and how to walk that tree at runtime to recover its state information. The article concludes by developing sample code to build and walk a parse tree that you'll generate for a small portion of the XQuery grammar.

Among bigger software players outside of the database realm, none has been faster off the block to promote XQuery than BEA Systems. The company forged a deal with and then bought XQuery software firm Enosys, maker of Liquid Data, and has brought aspects of that technology into its own suite ever since. All this is part of the company’s efforts to make integration a less-intensive task for developers. And just last month, BEA Systems announced the general availability of BEA Liquid Data for WebLogic 8.1.

The XQuery data model recognizes seven types of nodes. Learn how to take advantage of the data model in XQuery expressions

In some ways, querying XML documents is like going “back to the future” for anyone who remembers the days of hierarchical database management systems (DBMSs).

XML Query Language will soon become the "SQL for XML." Be prepared for the next version of Microsoft SQL Server by using a preview of the Microsoft.Xml.XQuery classes.

The goal of this article is to demonstrate the use of XQuery to accomplish a routine, yet interesting task; in particular, to render an HTML page that merges RSS news feeds from two different weblogs. RSS has earned its popularity by allowing people to easily share news among and between web sites. And for almost any programming language used on the Web, there is a good selection of libraries for consuming RSS.

XQuery is still a relatively new and unfamiliar XML-based language, but it offers many possibilities for simplifying tasks that today are difficult or tedious. These five practical scenarios should give you ideas for leveraging XQuery in your own applications.

In this article we will show to to write and install a very simple "web application" written in the XQuery language. We will also show you how errors are handled, and how you can debug them. Our application uses the servlet extension of Qexo (version 1.7 or later), a Free implementation of XQuery.

Learn how to use XQuery's FLWR (for, let where, and return) expressions to process and restructure data from one or more documents.

Let's face it, one of the primary tasks we, as Web developers, are faced with is querying data from some data store and allowing users to view and/or manipulate the information via a Web interface. Typically, the data stores that we query from are traditional relational databases, like Microsoft SQL Server or Oracle. With relational databases, the de facto means for querying data is SQL. However, with the ever-continuing rise in the popularity of Web services, and the need for a platform-independent, Internet-transferable data representation format, XML data stores are becoming more and more popular. SQL was never designed for querying semi-structured data stores, and therefore is not suitable for querying XML data stores. (For more information on creating and using Web services in ASP.NET be sure to read: Creating and Consuming a Web Service. For more information on XML be sure to read the XML FAQ Category on ASPFAQs.com.)

When you combine XML with URLs, great things happen. These two factors together make the endpoints of a transaction transparent to the kind of technologies that are on the other ends. However, this transparency can break down in the presence of databases. XQuery was proposed as a solution to this conundrum. Kurt Cagle looks at the structure and language of XQuery.

XML has emerged in only five years as a startlingly powerful means of handling data. It has also been accompanied by a slew of "X-centric" helper tools, APIs and standards such as XSLT, XPath and, of late, XQuery.

This column looks at the current state of the XML Query (a.k.a. XQuery) working draft. Kevin Williams shows how to use the FLWR ("flower") clauses, introduces the distinct-values function (which lends itself to pivoting data relationships), and offers his assessment of how XQuery will affect data document manipulation. Code samples in XQuery and XML demonstrate the use of for, let, where, and return (FLWR) clauses.

XQuery 1.0 is a language that allows users to search for and extract information from databases and documents. Here's how it works and who is using it.

We’ve all seen those commercials for some magic omni-tool that can screw, sand, carve and sharpen assorted objects, as well as remove stubborn grass stains. Most builders would scoff at the idea of replacing all of their specialized implements with an omni-tool, but is XML a different story? After all, with XQuery approaching recommendation status, one could argue that XML is about to get its very own omni-tool.

IBM's own XQuery pioneer Don Chamberlin discusses the emergence of the XQuery language -- specifically, the need for a query language for XML data, and the basic principles behind it. This excerpt is from Chapter 2 of the newly-released Addison-Wesley book XQuery from the Experts.

XQuery has been gaining momentum over the last year and looks like it will become a very important technology to server-side Java programmers, and probably all back-end programmers really. I've gotten into it big time over the last year and have found it fun and productive, and it's only getting better as the spec gets solidified and vendors start having robust implementations.