Hi all, more noob questions:
I'm trying to write something that will retrieve the resource for exactly one
file for which I have the URL
from a drag and drop operation... I'm using the Nepomuk::Query stuff because,
to be honest, I can't
make head nor tails of SPARQL yet.
So for starters:
- I know that I have a valid URL for a file
- I know its is in the database and
- using NepSAK I know that the resource has both NFO::fileName and NIE::url
associated.
I was thinking that NIE::url would be the thing to compare against:
QString urlstring = url.toString();
Nepomuk::Query::ComparisonTerm term (
Nepomuk::Vocabulary::NIE::url(),
Nepomuk::Query::LiteralTerm ( urlstring ),
Nepomuk::Query::ComparisonTerm::Equal
);
But this doesn't return any results, even when I know for certain that the file
has a resource with the
NIE::url property that has the value I'm looking for. Changing 'Equal' to
'Contains' doesn't work either.
Using NFO::fileName works fine, but returns several results if there's a
duplicate in the file system:
QString filename = urlstring.right ( ( urlstring.length() -
urlstring.lastIndexOf ( '/' ) )-1 ); // yeah, ugly...
Nepomuk::Query::ComparisonTerm term(
Nepomuk::Vocabulary::NFO::fileName(),
Nepomuk::Query::LiteralTerm(filename),
Nepomuk::Query::ComparisonTerm::Contains
);
Using the FileQuery class does not help (but adds some constraints to the
SPARQL).
I've also tried to use just the filename and 'Contains' against NIE::url, and
that doesn't work either.
As I said, I'm pretty clueless with SPARQL, but when I take the Query generated
SPARQL and paste
into NepSAK the results are the same (obvious) but when I replace the
nfo::fileName with nie::url it also
doesn't work which is not very obvious to me eg:
select distinct ?r , ?v1 as ?_n_f_t_m_ex_ where { ?r nie:url ?v1 .
FILTER(bif:contains(?v1,
"'095262r00ZB_zigbee_rf4ce_sc-ZigBee_RF4CE_Specification_public.pdf'")) .
FILTER EXISTS { ?r a
[ nao:userVisible "true"^^XMLSchema:boolean ] . } . } LIMIT 20
I'm guessing I'm missing something obvious here...
cheers,
dean
Oh and secondary questions:
(1) the generated query has the stuff between ?r and ?v1 which seems extraneous
and seems to return
a result with HTML markup (<b></b> tags) that disappear if I remove them:
select distinct ?r
(bif:concat(bif:search_excerpt(bif:vector('095262r00ZB_zigbee_rf4ce_sc-
ZigBee_RF4CE_Specification_public.pdf'), ?v1))) ....
vs
select distinct ?r, ?v1 ....
produces
<b>095262r00ZB</b> zigbee rf4ce sc ZigBee RF4CE Specification public.
vs
095262r00ZB_zigbee_rf4ce_sc-ZigBee_RF4CE_Specification_public.pdf
(2) is it just me or does the 'bool' parameter for
QueryServiceClient::syncQuery always return 'false' ?
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