Hugh Williams wrote:
Rob,
Querying against the officially host Virtuoso DBpedia endpoint
(http://dbpedia.org:8890/sparql), the second query does return a single
result as you expect. So it would appear their is something wrong most
probably with your DBpedia datasets loaded I would think. When you state
having "a fairly complete en version of the DBpedia dataset loaded into
Virtuoso OS" how complete is this are they some datasets you have not
loaded ?
I have a 15Gb virtuso db with the following loaded :
articles_label_en.nt
shortabstract_en.nt
longabstract_en
wikipage_en.nt
articlecategories_en.nt
externallinks_en.nt
infobox_en.nt
infoboxproperties_en.nt
pagelinks_en.nt
homepage_en.nt
redirect_en.nt
disambiguation_en.nt
categories_label_en.nt
So I have the redirects dataset loaded. I would have thought since the
following returns a redirect :
SELECT ?p ?o WHERE { <http://dbpedia.org/resource/Programmers> ?p ?o
p : http://dbpedia.org/property/redirect
o : http://dbpedia.org/resource/Programmer
That this should also work :
SELECT ?o WHERE { <http://dbpedia.org/resource/Programmers>
<http://dbpedia.org/property/redirect> ?o }
I guess I'm asking is there a situation where the first query could
return the result it does but the second query could return no results ?
I'm coming at this from a relational DB perspective, so the world of
triples is still a little new to me :)
My other thought was am I missing an index or could it be possible that
I have a corrupted index ?
Thanks for the help - much appreciated.
Best Regards
Hugh Williams
Professional Serviced
OpenLink Software
On 30 Apr 2008, at 14:06, robl wrote:
Hi,
I have a fairly complete en version of the DBpedia dataset loaded into
Virtuoso OS. I can perform the following query and it returns data as
expected :
SELECT ?p ?o WHERE { <http://dbpedia.org/resource/Programmers> ?p ?o }
Which returns one result :
p : http://dbpedia.org/property/redirect
o : http://dbpedia.org/resource/Programmer
When I execute this query however, there are no results returned :
SELECT ?o WHERE { <http://dbpedia.org/resource/Programmers>
<http://dbpedia.org/property/redirect> ?o }
I'd expect this to return :
o : http://dbpedia.org/resource/Programmer
Have I misunderstood something here or is my virtuoso installation/data
flawed in some way ?
Thanks,
Rob
-------------------------------------------------------------------------
This SF.net email is sponsored by the 2008 JavaOne(SM) Conference
Don't miss this year's exciting event. There's still time to save $100.
Use priority code J8TL2D2.
http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone
_______________________________________________
Virtuoso-users mailing list
Virtuoso-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/virtuoso-users
