[Nepomuk] Problem with nepomuksearch

[Peter Penz]

On Thursday, 3. December 2009 22:04:11 Sebastian Trueg wrote:
[...]
> > I build the comparison term this way:
> >
> > Nepomuk::Query::ComparisonTerm term(prop, literal, comp);
> >
> > In my testcase the values are:
> > - prop:
> > QUrl("http://www.semanticdesktop.org/ontologies/2007/08/15/nao#lastModifi
> >ed") - literal:
> > [Literal "2009-01-01"^^<http://www.w3.org/2001/XMLSchema#date>]
>
> This is already incorrect as the range is QDateTime. Maybe I could add
> conversion support to libnepomukquery...

I've adjusted it to use QDateTime and the result looks like this now:

[Literal "2008-12-31T23:00:00Z"^^<http://www.w3.org/2001/XMLSchema#dateTime>]

[...]
> > This looks OK. Afterwards I'm doing something like this:
> >
> > Nepomuk::Query::Query query;
> > query.setTerm(term);
> > KUrl url = query.toSearchUrl();
> >
> > and url will be:
> > KUrl("nepomuksearch:/?sparql=select distinct ?r  where { ?r
> > <http://www.semanticdesktop.org/ontologies/2007/08/15/nao#lastModified>
> > "2009-01-01"^^<http://www.w3.org/2001/XMLSchema#date> .    }")
>
> This is a bug which I did not look into yet either. But I know of it. :P

I've manually adjusted the search to:
nepomuksearch:/?sparql=select distinct ?r  where { ?r 
<http://www.semanticdesktop.org/ontologies/2007/08/15/nao#lastModified> >= 
"2008-12-31T23:00:00Z"^^<http://www.w3.org/2001/XMLSchema%23dateTime> . }

but get no result... Is this query correct?

> > So it seems that the >= operator has been removed... I tried to add it
> > manually, but also get no results... Since my update to Virtuoso also
> > "hand made queries" like:
> >
> > nepomuksearch:/tag:TestTag1
> >
> > don't give a result, although there is a tagged file with this tag (see
> > http://enzosworld.gmxhome.de/temp/search1.png and
> > http://enzosworld.gmxhome.de/temp/search2.png). At least just listing the
> > tag works: http://enzosworld.gmxhome.de/temp/search3.png
>
> That is because "tag" matches way too many properties which results in
> amazingly long queries. Using "hastag" works though.

This was a good hint, thanks :-) I've adjusted the Dolphin code now and at 
least searching for tags works very nice again.

> I am not sure on how to improve that situation other than maybe only
> selecting used properties. But the problem with that is negated terms.
> There you also want unused properties I suppose...

I've deactivated the "!=" operator for tags for Dolphin at least in KDE SC 
4.4.0 (I've left in the string so that I could reactivate it later during KDE 
SC 4.4.x). So from a Dolphin point of view there is no need to have a solution 
before KDE SC 4.4.0...

But for sure it would be nice having negated terms including unused 
properties... I agree here with Alessandro: having a != enum to the 
ComparisonTerm operators would be great, but I guess there was a reason why 
you did not add it there yet ;-)

>
> > Any hints would be very welcome! Thanks,
> > Peter
> >
> > _______________________________________________
> > Nepomuk mailing list
> > Nepomuk at kde.org
> > https://mail.kde.org/mailman/listinfo/nepomuk