If a recent survey is any indication, demand for a standard way to see a
database table as an XML document is blossoming.
Working XQuery DynCorp engineer Michael Ritchson said he and his team needed a technology that could handle the querying tasks NASA was expecting.
Sandeepan Banerjee, director of product management for XML at Oracle, said
According to research from XML
Another 33 percent have plans to start using XQuery in 2005, said Larry Kim,
XML products manager for DataDirect, and author of the report on XQuery
adoption.
XQuery is important because it builds on XML, which describes the
content of structured data, relational databases and object repositories.
The spec uses XML to express queries across all these kinds of data,
regardless of whether it is stored in XML or viewed as XML via middleware.
A purchase order is a classic example of how the spec is used to make life
easier for developers, and ultimately, end users. Kim said programmers can
take a purchase order from one vendor format and make it into another
vendor’s PO format by taking XML data and publishing it to the Web.
This data could then be shuttled, exchanged or stored as Web services
connecting software across disparate networks.
Developers may also use XQuery to query vast data stores of XML. For
example, Kim said NASA recently tabbed systems integrator DynCorp to develop
statistical analysis software for various types of aircraft data.
“After many months of research, our development staff decided to utilize
XQuery as our technique of choice to query XML data stored in an XML
database,” Ritchson said. “We now use XQuery for extracting data from
structured XML documents stored in an XML database, and this process has
dramatically improved the querying capabilities of our existing
applications.”
Kim’s finding is the fruit of a report he wrote after surveying 550 software
developers from small, medium and large companies. While the news is
encouraging for DataDirect, which makes a software tool that hooks XQuery
into the Java API
the spec is being taken up with such interest.
“XML is pervasive as a popular way of expressing information and data, and
yet there is still no standard way of manipulating, querying, accessing and
transforming XML,” Kim said in an interview.
Kim is referring to the fact that XQuery is still a few months away from
passage as a standard within the World Wide Web Consortium (W3C), where it
is an actual project with a host of specs. XQuery 1.0 is the language
Kim focused on for his survey.
W3C spokesperson Janet Daly said more than half of the specifications on the list are now in their second to last call. This is the stage a spec enters
when the technical group working on it is ready for other groups to review it to ensure that dependencies have been addressed.
Vendors Consider XQuery For Web Services
XQuery’s incompleteness isn’t stopping vendors like Oracle and IBM from
including it in forthcoming versions of their enterprise-class database
software.
Oracle will have a full implementation with release 2 of Oracle 10g
Database, slated for late summer.
While the engineer believes there is a place for XQuery, he doesn’t think it
will replace traditional languages like SQL, at least not in the next few
years.
“We take XQuery seriously,” Banerjee said in an interview. “We see it as
having the potential for becoming an important query language. I don’t think
XQuery will be the only query language in the next one to two years because
we see highly structured data still being searched by SQL. We also see
unstructured data being searched by Google search engines.”
Rather, the engineer said XQuery will have a market niche that is somewhere
in the middle, where the data is all XML or has some structure to it.
“Enough to query on, but not so much structure that you’re better off
putting it in a relational database and doing SQL on it,” he said.
Paul Rivot, director of competitive technology for IBM, agreed with Banerjee
for the most part, noting that IBM will have full XQuery support in the
follow-up to its Stinger DB2 Universal Database release.
That update isn’t likely to beat Oracle’s 10g release 2, but it will appear
before 2006. Until then it’ll bake in preparation for the next DB2 beta.
Rivot said one of the challenges his company faces is querying relational data and XML at the same time and making them transparent, so that people that
know SQL can leverage XQuery and use its capabilities to integrate both
languages.
“We see a lot of promise in using XML and XQuery to move data back and
forth, and we think it will be particularly useful for Web services
This makes sense because most Web services are written in XML, making XQuery
a natural back-end support mechanism for broad application-to-application
communication. But the matter depends on the context, Banerjee said.
“Web services search is going to be used widely,” Banerjee said. “To some
extent whether XQuery is used as a query syntax for Web services depends on
what the services do. Keyword searches don’t need it. If they do complex
things like purchase-order invoices, there is more space for XQuery to be a
Web services query syntax.”
Forrester Research analyst Noel Yuhanna said he sees XQuery as something
that will be used to tie together newer applications that require greater interaction or integration with data repositories. The idea that XQuery is becoming a standard is exciting to people who want to develop more XML-based software for grid computing and Web services, he said.
“These are customers who want to put an effort in XML because it provides
better data sharing, which is essential when dealing with real-time
information,” Yuhanna said. “XML has had a slow start but we’re certainly
seeing it as more appealing with new applications.”
For the near term, both Banerjee and Rivot thought Kim’s outlook may be a
tad optimistic, considering that it was culled from XML fans. But they
agreed that XQuery has more promise now than ever despite the fact that herds
of specs are months away from becoming standards.
In fact, Banerjee went so far as to predict a convergence of SQL, XQuery and
keyword queries of unstructured Google in five or more years. That will be
just fine for Kim, who said he believes strongly in the broad applicability
of XQuery.
