On Mittwoch, 16. April 2008, Aerik Sylvan wrote:
S Page wrote:
Aerik Sylvan wrote:
At the risk of asking a stupid question: what is
the status of
category intersections?
At the risk of making a stupid answer: you could install the Semantic
MediaWiki extension and make queries like
{{#ask:
[[Category:Actor]]
[[Category:Director]]
}}
SMW will query for membership of subcategories (thus it'll match members
of Child actors) , to a configurable depth limit. The nifty thing is
you can
display other properties and categories of matching pages.
See demo (temporarily) at,
http://www.semanticweb.org/wiki/Sandbox#Category_intersections
That's cool... what's the backend for that? (I looked briefly at some docs
at
http://semantic-mediawiki.org/wiki/Semantic_MediaWiki but didn't quickly
find any architecture stuff).
Better late than never: the intersections currently are computed with
straightforward SQL calls using joins. Before that, the query that a user
enters is parsed and pre-processed (e.g. to limit the complexity of the
query). It would be nice if we could have some faster backend for category
intersections, e.g. using column-based DBs or fast RDF-stores instead of
MySQL. Changing the storage backend in SMW can be done in a very modular
fashion, since all concrete methods for accessing SQL are in one file -- the
rest of the system uses interface methods instead of direct SQL calls.
Cheers
Markus
Best Regards,
Aerik
--
Markus Krötzsch
Institut AIFB, Universität Karlsruhe (TH), 76128 Karlsruhe
phone +49 (0)721 608 7362 fax +49 (0)721 608 5998
mak(a)aifb.uni-karlsruhe.de www
http://korrekt.org