Sorry I forgot to add reference. Here it is:
[1] http://www.w3.org/2009/sparql/wiki/Feature:Negation
Regards,
Ondrej
On 12/01/2011 04:46 PM, Ondrej Zamazal wrote:
Hi,
I am using ARQ in Jena and I am trying to figure out how I could query
that a certain triple does not exist in the graph (negation as failure).
I found the document [1] where UNSAID operator is mentioned but it
seems that this is not supported by ARQ. Right? There is also
mentioned that combination of OPTIONAL and FILTER could work for some
cases. But I think that this is not sufficient for my case because
there are not unbounded variables in my query, please see below.
In the query I would need to ask whether the specific triple is
missing in a graph, e.g.
SELECT *
WHERE {
UNSAID { <http://ontology1#Concept1> rdfs:subClassOf
<http://ontology1#Concept2> }.
}
I think UNSAID should be good for this case or maybe something like
'not ASK'. I would just need yes/no answer from query engine.
Would this be somehow possible?
Thank you for your reply in advance
Regards,
Ondrej
