Re: [Virtuoso-users] DBpedia and Virtuoso SPARQL Query

[Hugh Williams]

Rob,
On 30 Apr 2008, at 13:52, robl wrote:

Hugh Williams wrote:

Hi Rob,
The following change to the query should work:
SELECT ?subject ?predicate ?object WHERE {
  ?subject ?predicate ?object.
  ?object bif:contains "'%Queen%Elizabeth%'"
}
Note the single quotes around the % characters.

Doesn't this match objects rather than subjects though ? I don't think thats what was required ?

[Hugh] This is how Virtuoso handles phrases in bif:contains.

Regards
Hugh

Best Regards
Hugh Williams
Professional Services
OpenLink Software
On 21 Apr 2008, at 14:40, robl wrote:

Hi,

I'm currently working with the latest DBpedia dataset in Virtuoso OS
Edition (5.06).  I'm trying to do the equivalent of a SQL LIKE using

SPARQL on a resource subject. So in SQL this would have been something

like :

SELECT * FROM pages WHERE page_title LIKE "Queen%Elizabeth"

This would perform a case insensitive match on Queen(anything) Elizabeth

(at least in mySQL).

I have tried the following in my virtuoso instance :

SELECT ?subject ?predicate ?object WHERE {
   ?subject ?predicate ?object.

FILTER(?subject like "^http://dbpedia.org/resource/ Queen.*Elizabeth$")

}

SELECT ?subject ?predicate ?object WHERE {
   ?subject ?predicate ?object.
   FILTER regex(?subject,
"^http://dbpedia.org/resource/Queen.*Elizabeth$";, "i")
}

These both take well over a minute to return (and the first doesn't seem

to be case insensitive), which isn't acceptable for my particular
application.

Is there quick way to do what I want ? Are there any indexes I could apply to improve things (I have already created the indexes specified at http://www.openlinksw.com/dataspace/kide...@openlinksw.com/weblog/ kide...@openlinksw.com's%20BLOG%20%5B127%5D/1298)

?

Or do I need to create a conventional SQL table of resource names and

then do a SQL LIKE query on those ?

Thanks,

Rob

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