- From: Andreas Langegger <al@jku.at>
- Date: Mon, 9 Feb 2009 15:49:13 +0100
- To: "Rob Styles" <rob.styles@talis.com>
- Cc: "Juan Sequeda" <juanfederico@gmail.com>, "Georgi Kobilarov" <georgi.kobilarov@gmx.de>, "Hugh Glaser" <hg@ecs.soton.ac.uk>, "Yves Raimond" <yves.raimond@gmail.com>, <public-lod@w3.org>
> It seems to me that the data in an rdbms is often structured in ways > that are designed to be efficient for the rdbms to manage rather > than in ways that make sense externally. Levels of normalisation are > the main thing I'm thinking of. LD is most widely useful at 5th > Normal Form, but then there are tradeoffs that usually lead to an > rdbms schema being more like 3NF. I also think that this is the most crucial point. We can always say, well, it's easy, you just need to do this and that. But then comes the details. But on the other hand, you can do very complex mappings with D2R already to solve this. The only thing is lack of performance if you have many obscure mappings for a larger data set! > Isn't the effort in publishing LD the same effort that one expends > getting the data from the rdbms into HTML today, but that the data > needs to be in RDF? When doing that don't tradeoffs in the schema > have to be reconciled through queries that join from several tables > or that select distinct entries in particular columns? Isn't that > what Drupal and Ruby-n-Rails and so on are optimised to do? > > I agree with the notion of lowering the barrier and Virtuoso's > mapping stuff is really interesting, but is the cost really that > high right now? Isn't it just the same as writing some dynamic web > pages? I think it depends if you just want to provide some RDFa pages, or if you want to provide SPARQL. In the second case, you have to do a formalized mapping (e.g. with d2rq map or Virtuoso RDF views) > > > rob > > > Rob Styles > tel: +44 (0)870 400 5000 > fax: +44 (0)870 400 5001 > mobile: +44 (0)7971 475 257 > msn: mmmmmrob@yahoo.com > irc: irc.freenode.net/mmmmmrob,isnick > web: http://www.talis.com/ > blog: http://www.dynamicorange.com/blog/ > blog: http://blogs.talis.com/panlibus/ > blog: http://blogs.talis.com/nodalities/ > blog: http://blogs.talis.com/n2/ > Please consider the environment before printing this email. > > Find out more about Talis at www.talis.com > shared innovationTM > > Any views or personal opinions expressed within this email may not > be those of Talis Information Ltd or its employees. The content of > this email message and any files that may be attached are > confidential, and for the usage of the intended recipient only. If > you are not the intended recipient, then please return this message > to the sender and delete it. Any use of this e-mail by an > unauthorised recipient is prohibited. > > Talis Information Ltd is a member of the Talis Group of companies > and is registered in England No 3638278 with its registered office > at Knights Court, Solihull Parkway, Birmingham Business Park, B37 7YB. > http://www.langegger.at ---------------------------------------------------------------------- Dipl.-Ing.(FH) Andreas Langegger Institute for Applied Knowledge Processing Johannes Kepler University Linz A-4040 Linz, Altenberger Straße 69
Received on Monday, 9 February 2009 14:49:58 UTC