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RE: Is the ontology structure stored seamlessly with its data?

From: T.Heath <T.Heath@open.ac.uk>
Date: Tue, 2 Oct 2007 15:25:00 +0100
Message-ID: <E0FEA5DF00E59E409F90C854A1B45BAA0557ED37@EPPING-EVS1.open.ac.uk>
To: "Luciano, Joanne S." <jluciano@mitre.org>
Cc: "Semantic Web Interest Group" <semantic-web@w3.org>, "public-owl-dev-request@w3.org" <public-owl-dev@w3.org>

Hi Joanne,

You might have come across it already, but if not and if PHP is your thing then have a look at RAP [1]. I've only really used it for manipulating RDF instance data (I've never tried to work with OntModels in RAP, although these are supported) but it works pretty well for hacking around with relatively small data sets (i.e. up to a few hundred thousand triples, maybe more depending on what you want to do with them). The SPARQL engine for working with models persisted to RDBs has been rewritten in the latest version (0.9.5), which has significantly improved performance.

Others seem to swear by ARC [2] but have never used it so can't speak from experience.

Cheers,

Tom.

[1] http://sites.wiwiss.fu-berlin.de/suhl/bizer/rdfapi/
[2] http://arc.web-semantics.org/


> -----Original Message-----
> From: semantic-web-request@w3.org 
> [mailto:semantic-web-request@w3.org] On Behalf Of Luciano, Joanne S.
> Sent: 01 October 2007 17:54
> To: Michael Schneider; Emanuele D'Arrigo
> Cc: Semantic Web Interest Group; public-owl-dev-request@w3.org
> Subject: RE: Is the ontology structure stored seamlessly with 
> its data?
> 
> 
> 
> Can anyone suggest a non-Jena / non-Java alternative?
> 
> And for RDF (without OWL) also?  
> 
> Thanks,
> Joanne 
> 
> >-----Original Message-----
> >From: public-owl-dev-request@w3.org
> >[mailto:public-owl-dev-request@w3.org] On Behalf Of Michael Schneider
> >Sent: Wednesday, September 26, 2007 1:37 PM
> >To: Emanuele D'Arrigo
> >Cc: Semantic Web Interest Group; public-owl-dev-request@w3.org
> >Subject: RE: Is the ontology structure stored seamlessly with its
> data?
> >
> >
> >Hi, Emanuele!
> >
> >Emanuele D'Arrigo wrote at September 26, 2007:
> >
> >>Another thing that is not quite clear in my mind right now is this: 
> >>are the sets of triplets describing the class and property
> hierarchies
> >>of an ontology normally stored seamlessly alongside the 
> data that is 
> >>classified and characterized by those classes and properties?
> >
> >With OWL, for which an RDF mapping exists, this is technically
> possible
> >without a problem. And when you, for instance, use JENA [1], a
> >well known
> >RDF framework for Java, you generally /work/ with ontology 
> >based knowledge
> >bases in such a way (at least in principle). 
> >
> >With JENA, you typically build a view to your knowledge base in the
> >following way:   
> >
> >  1) Create a so called "Model", which is empty at the beginning
> >
> >  2) Read into this Model the RDF statements representing the
> >axioms of your
> >OWL ontology
> >
> >  3) Read into this Model the RDF statements of your knowledge base
> >
> >A "Model" in Jena represents an RDF graph, i.e. a set of RDF
> >triples. Now,
> >as long as you use a pure "Model", this only gives you a view to the
> >combined set of RDF triples, which come from both your OWL 
> >ontology and your
> >knowledge base. But if you instead use an "OntModel" (which 
> stands for
> >"Ontology Model"), you get an extended view to your RDF graph: 
> >Suddenly, you
> >have additional API functionality to access all your OWL classes and
> >properties, and the (explicit) sub-relationships between them (and
> many
> >other ontology specific features). The magic behind this is that the 
> >OntModel internally separates out all those triple subsets 
> within the 
> >combind RDF graph, which are RDF mappings for OWL axioms.
> >
> >So this is the situation (or at least a possible and 
> perfectly working 
> >situation), when you /work/ with knowledge data. This does not, 
> >however, mean that you should also /store/ ontological and 
> assertional
> >data together
> >in the same RDF graph. I think, in most cases it will be a 
> >better strategy
> >to have them separately stored. Then, you can easily reuse the 
> >ontology for
> >different knowledge bases, and combine them /on the fly/, 
> >whenever you want
> >to work with them.
> >
> >Cheers,
> >Michael
> >
> >[1] http://jena.sourceforge.net/ (JENA project page)
> >
> >--
> >Dipl.-Inform. Michael Schneider
> >FZI Forschungszentrum Informatik Karlsruhe
> >Abtl. Information Process Engineering (IPE)
> >Tel  : +49-721-9654-726
> >Fax  : +49-721-9654-727
> >Email: Michael.Schneider@fzi.de
> >Web  : http://www.fzi.de/ipe/eng/mitarbeiter.php?id=555
> >
> >FZI Forschungszentrum Informatik an der Universität Karlsruhe 
> >Haid-und-Neu-Str. 10-14, D-76131 Karlsruhe
> >Tel.: +49-721-9654-0, Fax: +49-721-9654-959
> >Stiftung des bürgerlichen Rechts
> >Az: 14-0563.1 Regierungspräsidium Karlsruhe
> >Vorstand: Rüdiger Dillmann, Michael Flor, Jivka Ovtcharova, Rudi
> Studer
> >Vorsitzender des Kuratoriums: Ministerialdirigent Günther Leßnerkraus
> >
> >
> 
> 
Received on Tuesday, 2 October 2007 14:25:37 GMT

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