Thanks, and especially thanks for the warning.
This does mean that I really do need the regex alternative, so having a
patch/solution for my
problem of non-functioning filter regex(str(?l),"query","i") through
jdbc is still urgent to me.
(For later when I have time to switch to VPL, a function returning the
number of matching keywords in the text-index per
query so given 'AB*' how many keywords are there would be useful e.g.
allowing to reformulate user queries containing
multiple words.)
Lourens
Hugh Williams wrote:
Hi Lourens,
Note, this limit is hard coded as a define in ~/libsrc/Wi/text.h of the open
source archive :
#define WST_WILDCARD_MAX 1000
So you would need to increase this to a suitable value and recompile the Virtuoso binary
for it to take effect. Note setting this value too high will make the execution of free
text queries inefficient, consider having words 'ABC', 'ABD', 'ABE' and wildcard 'AB*'
which in practice will be transformed to ABC OR ABD OR ABE , thus if each of these
returns a large number of matches the "OR"'ed list could become very long and
thus rather inefficient/slow. We may consider making this a configurable option with an
upper limit in the virtuoso.ini file in a future release.
Best Regards
Hugh Williams
Professional Services
OpenLink Software
Web: http://www.openlinksw.com
Support: http://support.openlinksw.com
Forums: http://boards.openlinksw.com/support
Twitter: http://twitter.com/OpenLink
On 15 Dec 2009, at 18:02, Lourens van der Meij wrote:
Hugh Williams wrote:
Hi Lourens,
This issue has not been resolved in the latest version, I have asked
development to schedule to look into this. In terms of work arounds I am not
sure how easily this can be done given the issue is only with case sensitive
matches. Virtuoso does have its own bif:contains function for Free Text search,
as detailed at:
http://docs.openlinksw.com/virtuoso/rdfsparqlrulefulltext.html#rdfsparqlrulefulltext
Which may be of use if you have not seen it already ?
Thanks Hugh for your answer and for asking development to look at it.
I use bif:contains at other places, but bif:contains has its own issue
that it cannot deal with result sets that match over 1000 keywords.
(and I suppose it would be awkward from within sparql to determine that
the match is at the start of the literal)
I need a FILTER regex(?l, "^a","i")
?l bif:contains "a*" would return an error because there are more than
1000 keywords in the index set of "a*" in my database.
Lourens
Best Regards
Hugh Williams
Professional Services
OpenLink Software
Web: http://www.openlinksw.com
Support: http://support.openlinksw.com
Forums: http://boards.openlinksw.com/support
Twitter: http://twitter.com/OpenLink
On 15 Dec 2009, at 10:25, Lourens van der Meij wrote:
The problem with regex "i" not working through JDBC is still giving me
problems. In the long run I hope
we will be able to stop using JDBC, but now we really need the functionality.
Could it be that the problem has been solved in a recent version?
I do notice that the problem does not occur when accessing Virtuoso through VSP.
If the problem has not been solved could you point me to a work-around? I am
not fluent in
the internals of Virtuoso, but I suspect that it should be possible to define a
stored procedure
that does the sparql call and that I could call that procedure through jdbc?
I seem to remember that it should even be possible to call a user defined
stored procedure from within sparql.
Then, would it be possible to define such a procedure that does the
regex(?l,String,"i") without the bug?
Thanks,
Lourens
Hugh Williams wrote:
Hi Lourens,
We have been able to recreate this issue in-house with the sample program you
provided and are looking into it. I shall report back when an update is
available ...
Best Regards
Hugh Williams
Professional Services
OpenLink Software
Web: http://www.openlinksw.com
Support: http://support.openlinksw.com
Forums: http://boards.openlinksw.com/support
Twitter: http://twitter.com/OpenLink
On 7 Nov 2009, at 19:11, Lourens van der Meij wrote:
Hi,
I am having the following problem:
Using the latest 5.0.12 version I do:
sparql insert into graph <gr> { <http://id>
<http://www.w3.org/2004/02/skos/core#prefLabel> 'test eng1'@nl .}
sparql PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
SELECT ?value from <gr>
WHERE {<http://id> skos:prefLabel ?value. FILTER
regex(str(?value),"test","i")}
through the jdbc4 driver from java and I get no results when expecting them.
The query without the "i" argument does give the correct result.
I get the correct result with the "i" option when testing through isql
and the 8890/sparql connection.
I add the java code illustrating this problem:
On my installation the first query gives 1 result.
The second query gives 0 results.
Could you tell me what is wrong?
Thanks,
Lourens
==============TestRegex.java========================
import java.sql.*;
import virtuoso.jdbc4.*;
public class TestRegex {
public static void main(String argv[]) {
try {
String urlDB =
"jdbc:virtuoso://localhost:1111/charset=UTF-8";
Class.forName("virtuoso.jdbc4.Driver");
Connection conn =
DriverManager.getConnection(urlDB,"dba","dba");
Statement st = conn.createStatement();
st.execute("sparql clear graph <gr>");
st.execute("sparql insert into graph <gr> { <http://id>
<http://www.w3.org/2004/02/skos/core#prefLabel> 'test eng1'@nl .}");
System.out.println("##### exec query regex without
i###############");
String query1 = "sparql PREFIX skos:
<http://www.w3.org/2004/02/skos/core#> \nSELECT ?value from <gr> \nWHERE
{<http://id> skos:prefLabel ?value. FILTER regex(str(?value),\"test\")}";
System.out.println("Running query:\n"+query1);
execQuery(st,query1);
System.out.println("##### exec query regex with
i###################");
String query2 = "sparql PREFIX skos:
<http://www.w3.org/2004/02/skos/core#> \nSELECT ?value from <gr> \nWHERE
{<http://id> skos:prefLabel ?value. FILTER
regex(str(?value),\"test\",\"i\")}";
System.out.println("Running query:\n"+query2);
execQuery(st,query2);
conn.close();
} catch (Exception e) {
System.out.println(e);
System.out.println("===========================================================");
e.printStackTrace();
}
}
public static void execQuery(Statement st, String query) throws
SQLException
{
ResultSet rs;
ResultSetMetaData rsmd;
rs = st.executeQuery(query);
rsmd = rs.getMetaData();
if (rsmd == null) System.out.println("getMetaData() == NULL");
int results = 0;
while(rs.next()) {
Object o;
System.out.println(" ============= < ROW > ============ ");
for (int i = 1; i <= rsmd.getColumnCount(); i++) {
results++;
String s = rs.getString(i);
o = rs.getObject(i);
if (rs.wasNull())
System.out.println(i+" ==> NULL");
else
{
if (o instanceof VirtuosoExtendedString)
{
VirtuosoExtendedString vs =
(VirtuosoExtendedString)o;
System.out.print("VirtuosoExtendedString:
[iri="+vs.iriType+"]");
}
else if (o instanceof VirtuosoRdfBox)
{
VirtuosoRdfBox rb = (VirtuosoRdfBox)o;
System.out.print("VirtuosoRdfBox:[rdf="+rb+";
type="+rb.getType()+";lang="+rb.getLang()+"]");
}
else
{
System.out.print(" |");
System.out.print(""+o.getClass()+"|");
}
System.out.println(" ==> ["+ o + "]");
}
}
}
System.out.println("got "+results + " results");
}
}
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