RDF – an Introduction

November 26, 2008

After deciding to implement the new OxPoints system with Semantic Web technologies (see OxPoints and the Semantic Web) I started to read up on all I could find on RDF (Resource Description Framework) and related technologies like RDFS and OWL. In particular I was looking for

  • specifications,
  • best practices and
  • reports on projects using RDF.

I was astonished to find that, even though many people talk about RDF, it seems that only very few have actually ever used it (i.e. outside academic studies). Or if they have, they at least did not tell anyone about it.
However, one thing, that I did definitely not expect to find was that there seems to be a fundamental design flaw in RDF. I thought about this a lot, and hope that by blogging about it, you will either tell me, that I am wrong and how to do it right, or that we might find a solution on how to solve the problem.

But before talking about what I think is wrong with RDF and proposing one way to solve that problem (yes, luckily I think there is a solution), we need to establish a common language, which is what I want to achieve with this introduction. If you are already familiar with RDF, you might want to have a look at the sections: Triples are Facts, Reification and Entailment. If you are new to RDF, I hope that this will give you a first start. However, I kept this introduction very short and so many aspects are missing. If you want to learn more about RDF I would recommend you to start with the RDF Primer, the introduction to RDF from the W3C. In most sections I have also linked the specific sections from the RDF Specifications.

I will try to assume as little previous knowledge as possible, but since RDF is not a trivial topic, I have to start somewhere. Basic knowledge of XML and some knowledge of mathematical notation would therefore probably be of help.

RDF (Resource Description Framework)

The Resource Description Framework (or short RDF) is a set of W3C specifications which were first published in 1999 and revised in 2004 (more information on the history of RDF can be found at its Wikipedia page or at the W3C pages on RDF). RDF is “a language for representing information about resources in the World Wide Web” (RDF Primer [http://www.w3.org/TR/REC-rdf-syntax/]).

So what are resources in the World Wide Web?

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