[seek-kr-sms] is there any query language in sparrow dl?

Serguei Krivov Serguei.Krivov at uvm.edu
Tue Sep 7 12:45:51 PDT 2004


 

What exactly do you want to query?  (e.g., for individuals -- i.e., data

-- or for classes, properties -- i.e., schema). Also, what query use
cases do you have in mind?

My suggestion would be to figure out why you want a query language and 
who the query language is for ....

Shawn,
In general I understand the importance of looking at the purpose and the
targeted users of a software or language. In fact I have been preaching
this idea myself very often and it was a kind of religion for me
sometimes back.  Yet now I also see that there are many languages and
programs of general interest. Examples may include - SQL, OWL, Protégé
or Growl :-).

Say SQL could be used for a variety of things and it is in a way a
natural for RDBMS. And my question is:  

Can we have a query language which is natural for DL and OWL databases
without any thoughts about rdfs? Should we have one, we could use it in
many applications, including ontology based search in Kepler or search
of documents on the web based on some ontology/metadata registry. 

Why to avoid rdfs? First- it is not natural media for DL things. Second,
my understanding is that traditional rdf triplestore either in Jena or
others is extremely inefficient for large applications and the main
problem is with using triples rather then with implementations. I have
some reviews on this subject and I would be glad to discuss this issue
if anyone is interested.    There are many issues of course to resolve
with DL QL, one is comparability with existing things -Racer  Query
Language, DIG (too simple thing) and half dozen of rdf oriented query
languages which may not work with owl though.  If as in OWL-QL (some)
queries require reasoning, the language would not find real
applications, since reasoning is at least ExpTime. Therefore it is
better to think about queering existing classified ontologies. One could
query only facts (Abox), but if ontology is assumed to be classified we
could also query TBox as long as we do not introduce new class
definitions in the query process (as OWL_QL allows).

Cheers,
Serguei






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