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Re: Upcoming wave of quad/namedgraph implementations ,was: Reification - whats best practice?

From: Alberto Reggiori <alberto@asemantics.com>
Date: Fri, 10 Sep 2004 11:45:37 +0200
Message-Id: <2B270BAB-030E-11D9-955E-0003939CA324@asemantics.com>
Cc: RDF Interest <www-rdf-interest@w3.org>
To: "Chris Bizer" <chris@bizer.de>

On Sep 10, 2004, at 11:14 AM, Chris Bizer wrote:

> Hi all,
> it really looks like this reification discussion make some people sit  
> down
> and work :-)
> We will see a wave of quad/namedgraph-based implementations being  
> released
> in the next weeks. Up to my knowledge, the following people are  
> currently
> working on implementations:
> 1. We are working on a NamedGraph API extending Jena
> http://www.wiwiss.fu-berlin.de/suhl/bizer/ng4j/
> 2. Andy Seaborne and Rave Reynolds work on a Jena Multimodel
> http://www.swed.org.uk/swed/doc/javadoc/com/hp/hpl/jena/util/ 
> MultiModel.html
> 3. Andrew Newman said that Kowari 1.0.5 will somehow support
> quads/namedgraphs (??),
> http://kowari.sourceforge.net/
> 4. Phil Dawes implements a store in python which will support
> quads/namedgraphs
> 5. RDF Gateway already supports quads
> http://www.intellidimension.com/default.rsp?topic=/pages/site/ 
> products/rdfgateway.rsp
> Anybody else?

as already reported in other discussion threads, we do quads in  
RDFStore to get graph-naming / context / provenance functionality


http://www.asemantics.com/presos/SWAD-E/SWADe-rdfstore.html (see  
context/provenance section and special table)

graph-names are simple RDF resources (URI or bNodes) which can be  
further described into RDF itself - the API exposes source/context  
specific methods too. And in our RDQL++ implementation we allow  
quads-like graph-patterns.

have a try with following query at  
http://demo.asemantics.com/rdfstore/rdql/ (or try to download the  
package and run the query with rdf.pl)

select ?name ?src
from <http://www.asemantics.com/people/alberto.rdf>
where (?person <foaf:name> ?name ?src)

quads information is exposed in RDF/XML using a simple rdf special  
property (which our parser understands) which can scope triples to  
different graph-names.


N-Triples inside become Quads though.

we are looking forward to hear from other implementers,  their code and  
ideas - and try to get a common consensus and way to implement such  
useful feature. Graph naming work already done seems a very good  
starting point - as well as other code already written be people here  
in the RDFIG.

thanks for pushing this topic further


Received on Friday, 10 September 2004 09:45:43 UTC

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