On 29 Nov 2010, at 14:13, Diogo FC Patrao wrote: >> The rewriting engine is not designed to work with multiple DBs, so >> sometimes it works by accident, but in general it won't. > > Do you think that if we configure the query rewriting module to not > JOIN > databases, that would work?
The easiest way of achieving this is running multiple instances of D2R Server. >> It would certainly be great if D2RQ had that ability. It's an open >> source project and contributions are always welcome ... > > That's definitely something I'm interested into, and would gladly > give some > of my employee's time to solve. Do you have an idea how exactly to > solve > this? Contact me in pvt if you wish. This goes into the direction of federated SPARQL queries. There is quite a bit of research already out there, but I don't think that any really practical solution has been described in the literature yet, so solving this likely requires a fair bit of original research. >> Anyways, if you want to integrate several data stores, at this point >> I'd recommend either using the basic federated query feature of Andy >> Seaborne's ARQ, or Extract-Transfer-Load them all into one triple >> store. > > you mean this ? http://jena.sourceforge.net/ARQ/service.html > > So I would have several instances on D2R-Server mapping different > databases > to the same ontology, then query them with ARQ using this SERVICE > statement? Yes. As stated on this page, it doesn't do any smart query planning, so essentially you have to do the query planning yourself when writing the query, but at least you can get results. See also: http://seaborne.blogspot.com/2007/07/basic-federated-sparql-query.html http://www.w3.org/2009/sparql/docs/fed/service (just a draft, I think it's not being further pursued by the working group at this point) Best, Richard > > ETL is not the ideal for me, I have several production databases I > want to > integrate, and I would avoid dealing with DW updates. > > Thanks, > > dfcp > > > >> >> Best, >> Richard >> >> >>> >>> Regards >>> Dr Christian Brenninkmeijer >>> University of Manchester >>> >>> >> ------------------------------------------------------------------------------ >>> Increase Visibility of Your 3D Game App & Earn a Chance To Win $500! >>> Tap into the largest installed PC base & get more eyes on your >>> game by >>> optimizing for Intel(R) Graphics Technology. Get started today with >>> the >>> Intel(R) Software Partner Program. Five $500 cash prizes are up for >>> grabs. >>> http://p.sf.net/sfu/intelisp-dev2dev >>> _______________________________________________ >>> d2rq-map-devel mailing list >>> [email protected] >>> https://lists.sourceforge.net/lists/listinfo/d2rq-map-devel >> >> >> >> ------------------------------------------------------------------------------ >> Increase Visibility of Your 3D Game App & Earn a Chance To Win $500! >> Tap into the largest installed PC base & get more eyes on your game >> by >> optimizing for Intel(R) Graphics Technology. Get started today with >> the >> Intel(R) Software Partner Program. Five $500 cash prizes are up for >> grabs. >> http://p.sf.net/sfu/intelisp-dev2dev >> _______________________________________________ >> d2rq-map-devel mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/d2rq-map-devel >> ------------------------------------------------------------------------------ Increase Visibility of Your 3D Game App & Earn a Chance To Win $500! Tap into the largest installed PC base & get more eyes on your game by optimizing for Intel(R) Graphics Technology. Get started today with the Intel(R) Software Partner Program. Five $500 cash prizes are up for grabs. http://p.sf.net/sfu/intelisp-dev2dev _______________________________________________ d2rq-map-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/d2rq-map-devel
