Marvin Lugair wrote:
Hi all!
This is more for the virtuoso folks but still cc-ing dbpedia.
Please give us some input if you can answer these questions:
I am trying text search in virtuos from isql against a locally loaded dbpedia.
*QUESTION ONE*
Why does bif:contains return faster than REGEX search, and why are they
returning a different number of counted rows? The search string is not the real
string but it does not change the question. Which should we use?
bif:contains uses Virtuoso's in-built Full Text Index engine. The
indexes are based on the "Literal Objects" in Triples.
Regex isn't based on the Full Text indexes.
(1) searching with with regex
SQL> sparql select count(*) where { ?s ?p ?o . FILTER regex(?o , "searchstring",
"i")};
callret-0
INTEGER
_____________________________________________________________________________
4344
1 Rows. -- 3895755 msec.
(2) searching with bif:contains
SQL> sparql select count(*) where {?s ?p ?o. ?o bif:contains "searchstring"};
callret-0
INTEGER
_______________________________________________________________________________
20737
1 Rows. -- 208426 msec.
*Question 2*
Why can't I search a property or subject?
SQL> sparql select count(*) where {?s ?p ?o. ?p bif:contains "searchstring"};
*** Error 37000: [Virtuoso Driver][Virtuoso Server]SQ074: Line 1: SP031: SPARQL
compiler: The group does not contain triple pattern with '$p' object before
bif:contains() predicate
at line 1 of Top-Level:
sparql select count(*) where {?s ?p ?o. ?p bif:contains "searchstring"}
A "Property" in a Triple is a URI not a literal.
Kingsley
THANKS!
Marv
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Regards,
Kingsley Idehen Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO
OpenLink Software Web: http://www.openlinksw.com
