First of all this "semantic week" thing is timely considering the hype the semantic web is getting this week now that somebody linked it to "Web 3.0." No, I am not kidding.

From Nick Carr, who writes about a New York Times Article (can not be pulled up without registration, so screw that).

"Web 3.0. Formerly known as the semantic web, but now rebranded for mass consumption, Web 3.0 promises yet another Internet revolution. It would, Markoff writes, 'provide the foundation for systems that can reason in a human fashion ... In its current state, the Web is often described as being in the Lego phase, with all of its different parts capable of connecting to one another. Those who envision the next phase, Web 3.0, see it as an era when machines will start to do seemingly intelligent things.'"

If you want to see a ton of hype in the making, just Google "semantic web and Web 3.0," and you'll see that both the Web 2.0 and SOA bloggers are alive and kicking about this "new concept."

Truth be told, I've been linking the semantic web to SOA for a long time. Just to name three times, you can go here, here, and even here, all written in 2003 and 2004, many presentations as well, typically at user group conferences. Not to mention this blog.

To be honest, however, not a lot of people cared until now. I knew it was going to be a big deal sooner or later. Semantics are just too important to too many things, and everything when you consider them in the context of application integration and SOA.

So, what is the Semantic Web?

From Wikipedia:

"The Semantic Web is a project that intends to create a universal medium for information exchange by putting documents with computer-processable meaning (semantics) on the World Wide Web. Currently under the direction of the Web's creator, Tim Berners-Lee of the World Wide Web Consortium, the Semantic Web extends the Web through the use of standards, markup languages and related processing tools."

So, if you're looking to manage semantics in the context of a SOA, what tools and standards do you have at your disposal here?

The Semantic Web uses XML, XML Schema, RDF, RDF Schema and OWL.

XML Schema is a language for restricting the structure of XML documents.

RDF is a simple data model for referring to objects ("resources") and how they are related. An RDF-based model can be represented in XML syntax (more on this tomorrow).

RDF Schema is a vocabulary for describing properties and classes of RDF resources, with a semantics for generalization-hierarchies of such properties and classes.

OWL adds more vocabulary for describing properties and classes: among others, relations between classes (e.g. disjointness), cardinality (e.g. "exactly one"), equality, richer typing of properties, characteristics of properties (e.g. symmetry), and enumerated classes.

We'll touch on RDF, OWL, and more on the semantic web and SOA tomorrow.

Posted by Dave Linthicum on November 15, 2006 05:48 AM