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XQuery Blasts Off at NASA

How DynCorp (CSC) used XQuery at NASA's Johnson Space Center to Simplify XML Data Access and Integration

MICHAEL RITCHSON is a systems integrator employed with a DynCorp (recently bought out by CSC), who is the present contractor for NASA's Aircraft Operations in Houston, Texas. His duties include Architecting and developing JAVA J2EE web applications for their managers, team leaders, and employees, which vary from Quality Document routing systems to CRM tools. This story is about Michael's XQuery experiences, in his own words:

The Challenge

Our project team was asked to develop statistical analysis software for various types of aircraft data on behalf of our managers and to our end customer, NASA. In the past year our managers have been requesting enhanced techniques in data querying and extraction. Because the aircraft data is structured in an XML format, we needed a technology that could handle the querying use-case capabilities that our managers were expecting – this is where the use of XQuery really shines. 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. 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.

Why XQuery?

There were many factors which made us come to the conclusion that we did – overall we were impressed by XQuery power, ease of use, performance and value.

• The power of XQuery really shines when the user has the capability to query multiple XML documents simultaneously. This performance enhancement has made our job easier by presenting our managers with a very powerful tool to extract analytical data through our applications. Additionally, the XML database that we used included an XQuery Java API for extracting data which was invaluable for middleware integration work.
• We had several existing applications that used XPath technologies which are used extensively by XQuery technologies. Because XQuery employs a similar syntax to XPath, we found that it was relatively easy for us to learn and implement XQuery into our applications.
• XQuery performance is impressive – the speed of returning results in a whole collection is a far cry easier then mixing and matching different technologies like procedural code, XSLT, SQLXML, etc. We were so overwhelmed by the XQuery performance that it allowed us to increase our existing application requirements for applications.
• Another advantage of using XQuery is that it's an open standard being developed by the W3C – the main benefit of this is that with open standards is that there are many open source components and products which reduces the cost associated with XQuery (which is nothing) and sure beats the yearly licensing fees of using other proprietary data integration platforms.

It's rare in this business that you come across a software technology that is more powerful, easier to use, faster, actually lets us increase application requirements, and not to mention, is free to use– but in truth, that was our experience with XQuery
and we were thrilled with the results.

On The Importance of an XQuery API

Having a Java API for XQuery is important because it affords us with more possibilities in terms of application extensibility, customization, as well as a more seamless integration with existing applications. XQuery (contrary to how it's name suggests)
to us is more then just a neat new way to query XML data – as with any systems integration project, we had existing middleware applications which needed to be leveraged and using a Java API's for XQuery made a seamless integration possible. Previously, we were utilizing SQLXML, a XML data extraction method built into SQL Server 2000 for this kind of work. Now, utilizing the XQuery API's and the XML repository, we can move from SQLXML technologies to incorporate a more unified solution. Using the XQuery API also enabled us to build the application faster in that we found that it was very helpful in reducing our development / testing / deployment time was as a result of being able to use XQuery on the client and in the mid-tier.

On XQuery in the Middle Tier and as a Web Service Enabling Technology

We're excited about XQuery from a middleware perspective, too. We have written java middleware code that invokes XQuery expressions against the eXist XML database and aggregates structured XML documents without having to write redundant Java methods. Additionally, we view XQuery as being an important "Web Service" technology
– we wrote clients that invoke XQuery expressions using XML-RPC calls, which resulted in our development time been reduced. This architecture also benefits the server load requirements due to the capability to separate the web application, XML repository, the XML-RPC server, and the Middleware location. We are also looking into a SOAP implementation for web services modeling the SOA architecture.

On XQuery Tools

Using Stylus Studio, our development time has been even more reduced
due to the extensive XQuery tools. The XQuery feature has helped tremendously
in building the correct XQuery expressions required for querying and testing our structured XML documents. Also, the various XQuery wizards have been a
great help in learning the XQuery syntax required in our existing application.

XQuery: Not Only for Rocket Scientists

XQuery has really opened the door to how an application can be designed, developed and deployed. In the past, we were dreading having to write our own specific methods to query all the stored XML documents. But with the implementation of the XQuery API technology, our main focus has been on the specific business rules that are required by our organization. To me, the bottom line for choosing XQuery was satisfaction – to make our managers happy and also our customer, NASA.

About CSC

Founded in 1959, Computer Sciences Corporation is a leading global information technology (IT) services company. CSC's mission is to provide customers in industry and government with solutions crafted to meet their specific challenges and enable them to profit from the advanced use of technology.

With approximately 79,000 employees, CSC provides innovative solutions for customers around the world by applying leading technologies and CSC's own advanced capabilities. These include systems design and integration; IT and business process outsourcing; applications software development; Web and application hosting; and management consulting. Headquartered in El Segundo, Calif., CSC reported revenue of $13.9 billion from continuing operations for the 12 months ended Dec. 31, 2004. For more information, visit the company's Web site at www.csc.com.

About NASA

The National Aeronautics and Space Administration (NASA) was founded in 1958 with the mission to (a) Advance and communicate scientific knowledge and understanding of the Earth, the solar system, and the universe and use the environment of space for research (b) explore, use, and enable the development of space for human enterprise. (c) research, develop, verify, and transfer advanced aeronautics, space, and related technologies.