After writing a few paid articles and doing a lot of blogging about various issues, features, and trends surrounding the Semantic Web, Linked Data, RDF, RDFa, SPARQL, OWL, and related tools and implementations, I thought it would be nice if I could tie them together into something resembling a cohesive whole. So, I wrote a short essay titled RDF, The Semantic Web, and Linked Data with over 70 footnote links to these various pieces. It will be a handy reference for me in the future, and I hope it…

After the initial burst of discussion about Google putting their toe into the standardized metadata water, I started wondering about the corner of the pool they had chosen. They’re not ready to start parsing any old RDFa; they’ll be looking for RDFa that uses the vocabulary they somewhat hastily defined for the purpose. Why does the vocabulary define the properties that it defines?

Open Anzo is the third disk-based triplestore that I managed to set up, load with a few files of RDF data, and query with SPARQL. Its home page describes it as “an open source enterprise-featured RDF store and service oriented middleware platform that provides support for multiple users, distributed clients, offline work, real-time notification, named-graph modularization, versioning, access controls, and transactions with preconditions”.

As I wrote in my last entry, I’ve recently figured out how to assign metadata to RDF graphs and to perform SPARQL queries on sets of those graphs. I’m working a bit backwards here, because I’m now moving on to the use cases that got me thinking about this in the first place. It’s easier to think about them now that I know that I can implement them using standard syntax and multiple open source implementations of that standard. I wanted to outline my ideas about how to…

I’d like to thank everyone who added comments to my last post, Some questions about RDF named graphs. Lee Feigenbaum wrote an entire blog post addressing the issues I raised, and it looks like his Open Anzo triplestore (which I’ll write up in its own post soon) has some nice support for versioning, access control, and replication.

Most triplestores support named graphs, and from a high level I can see how they’d be useful, but as I think about using named graphs to address specific application needs, some questions come to mind, so I thought I’d throw them out there.

Just about all the RDF triplestores I’ve been trying were designed from the ground up to store RDF triples. OpenLink Software’s Virtuoso is a database server that can also store (and, as part of its original specialty, serve as an efficient interface to databases of) relational data and XML, so some of my setup and usage steps required learning a few other aspects of it first. For example, the actual loading of RDF is done using Virtuoso’s WebDAV support, so I had to learn a…