On August 24, 2004, Tom Bradford announced the production release of dbXML 2.0 on his personal Web site. It's an interesting way for the news about this technology to get out, and I've got to thank Robin Cover for catching this item and publicizing it on his excellent Web site, the Cover Pages.
With these necessary antecedents and preliminaries out of the way, what's the big deal here? dbXML 2.0 is a pretty darned interesting phenomenon, for all kinds of reasons. For one thing, it's a true open source project released under the aegis of the GNU General Public License (which requires that the source code accompany any software issued under this license)—an open technology book, in other words. For another thing, it's entirely XML-based and thus extremely well-suited to storing and organizing collections of XML documents, and can also handle all kinds of complex queries, document transformations, and retrieval operations. It's also been rewritten to use the Java 2 Standard Edition version 1.4 APIs (J2SE 1.4), which means it should compile and run on any platform (and there are a lot of them) where a runtime version of J2SE 1.4 is available.
dbXML 2.0 also offers the following features and capabilities:
- supports XML compression: this system permits documents storage in the form of tokenized streams, for faster performance and improved memory utilization
- caching techniques are used extensively to improve performance and response time
- XPath querying supports collection-level, index-based queries that employ indexes whenever they're available, and offer significant speed-ups on retrievals
- database triggers work as private database extensions so that content may be filtered when entering the database as input, or leaving it as output
- full-text indexing and querying
- plug-in security models
- brand-new command-line environment and client/server APIs
- transaction journaling
In addition, the new release also addresses bugs documented in the first release candidate, including SGML parsing problems, class incompatibilities, context handling issues, and RPC implementation problems (see Release Notes for details).
Commercial licenses are available to those organizations for which the terms of the GPL are not appropriate or acceptable (that is, where sharing of custom code may not be desirable or possible).
Developers interested in a full-featured, royalty-free, GPL DBMS implementation with strong XML document handling, transformation, and management capabilities will find dbXML 2.0 of great interest and potential value. See the resources list that follows next for pointers to information and documentation galore.
- dbXML Web site
- Source code, bug reporting, and CVS access at SourceForge dbXML project page
- Binary releases for Windows, Macintosh OS X, Solaris, Linux, and various Unix versions.
- dbXML Programmer's Guide
- Cover's summary "XML and Databases"
Ed Tittel is a writer, trainer, and consultant based in Austin, TX, who writes and teaches on XML and related vocabularies and applications. E-mail Ed at email@example.com.