RDFDB is an open source database written by R. V. Guha for storing and querying RDF information. It is fairly small and fast, and can work quite well on some systems. It is proof of the idea that RDF is not XML; RDF is actually a data model, and it can exist quite happily outside of XML.

RDFDB is currently is a pretty early stage of development. It has decent performance and a plain sockets-based interface, for which there are Perl and Java modules available. It uses a relatively simple SQL-like query language, allowing you to write things like this:

select ?x from test1 where (worksFor ?x W3C) (name ?x ?y) </>
?x = DanC ?y = 'Dan Connolly'
?x = DanB ?y = 'Dan Brickley'
0 </>

The "</>" bit is the end statement, like the semicolon in C or Perl. This is a great approach, and I wish Guha only the best. However, RDFDB has its issues. It doesn't run very well on Windows, no Python interface exists yet (or any other language besides Perl, for that matter), and it doesn't have the nice things you've become accustomed to in normal databases like password protection. Given these disadvantages, is it really worth it to consider RDFDB rather than just putting everything in a big MySQL database? Yes and no. RDFDB has great potential as a specialist database, since it can do things like using special data structures optimized for RDF. However, if you want something now, a conventional database back end would be a better choice.

There was an article on XML.com about RDFDb that explains more about the query syntax and gives more detailed examples, at

The home page is

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