Simple federated queries with RDF [Part 1]
Bob DuCharme writes:
A few more triples to identify some relationships, and you’re all set.
[side note] Easy aggregation without conversion is where semantic web technology shines the brightest.
Once, at an XML Summer School session, I was giving a talk about semantic web technology to a group that included several presenters from other sessions. This included Henry Thompson, who I’ve known since the SGML days. He was still a bit skeptical about RDF, and said that RDF was in the same situation as XML—that if he and I stored similar information using different vocabularies, we’d still have to convert his to use the same vocabulary as mine or vice versa before we could use our data together. I told him he was wrong—that easy aggregation without conversion is where semantic web technology shines the brightest.
I’ve finally put together an example. Let’s say that I want to query across his address book and my address book together for the first name, last name, and email address of anyone whose email address ends with “.org”. Imagine that his address book uses the vCard vocabulary and the Turtle syntax and looks like this,
Bob is an expert in more areas of markup, SGML/XML, SPARQL and other areas than I can easily count. Not to mention being a good friend.
Take a look at Bob’s post and decide for yourself how “simple” the federation is following Bob’s technique.
I am just going to let it speak for itself today.
I will outline obvious and some not so obvious steps in Bob’s “simple” federated queries in Part II.