Sharing my Brain – Another Result of the Nepomuk Workshop

If I learned anything at the Nepomuk workshop it is that too much information is just in my head and nowhere else. I tried to share it by writing API documentation and tutorials and blogs. But it never is enough. So today comes another dump from my brain: Nepomuk tips and tricks, a new chapter in the Nepomuk tutorial series. I hope it helps you to make more of the technologies Nepomuk provides.

9 thoughts on “Sharing my Brain – Another Result of the Nepomuk Workshop

  1. Hi, Sebastian,

    i would like to ask you as a pragmatic developer, why ontologies? After an hour of reading about the Nepomuk project, I haven’t found any reasoning or anything that is somehow different from simple resource description. Why not, e.g. some database + a web service (if sharing is one of the requirements)?

    Actually, I’m very sceptical when i read something like “Web 3.0 will soon be everywhere” or “Data integration across sources will be most important for companies in the near future.” Therefore your opinion is quite interesting for me. Thanks!


    • I don’t see the alternative and don’t really know what you mean by “simple resource description”. A relational database is always restricted to its table layout. There is no easy way to add new types and relations. And if you attempt to do that you very quickly end up with a system along the lines of RDF.

      • Basically put, you can use methods designed for handling this sort of data, or you can bootstrap other systems to do very much the same job but at a lower quality.

      • Rephrasing Henry Ford, you can have any type as long as it is string. RDF on its own has no types, just some declarations. In order to check the type you need additional programs that can analyse those declarations. BTW, don’t you aware of approaches that use databases to store RDF triples in order to speed up the processing? That’s only one of the examples of “easy way to add new types and relations.”

        Of course what i wrote above is just trivial answer on your question that can be given by everyone who knows a bit about RDF and databases. More complex answer will be that there are more general well-established logical programming approaches that can be used with databases, like datalog in which you are not limited to binary predicates, like in RDF, an which can handle major parts of Description Logics [1]. Moreover, in these systems you can also program and not only do type-checking.


        [1] Calì, A., Gottlob, G., and Lukasiewicz, T. 2009. Datalog±: a unified approach to ontologies and integrity constraints. In Proceedings of the 12th international Conference on Database theory (St. Petersburg, Russia, March 23 – 25, 2009). R. Fagin, Ed. ICDT ’09, vol. 361. ACM, New York, NY, 14-30. DOI=

        • So are there any open-source implementations of such a database available that we could have used?
          I am sure there are a lot better solutions than RDF. It has a lot of flaws. But there is a lot of development going on around it, a lot of research, and a lot of RDF data flows around the internet for us to pick up and link to.
          Would this still be true when using an approach like datalog?

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s