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
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Dipl.-Ing.(FH) Andreas Langegger
Institute for Applied Knowledge Processing
Johannes Kepler University Linz
A-4040 Linz, Altenberger Straße 69
