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

From: Andrew Newman <andrew@tucanatech.com>
Date: Fri, 10 Sep 2004 21:32:28 +1000
Message-ID: <414190CC.3040408@tucanatech.com>
To: www-rdf-interest@w3.org

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/

AFAIK, our triple store has always had quads (well as far back as 2001 
anyway).  The session, the way that client code interacts with the 
server, has always had operations like "add(Triple, URI)".  Our Jena 
support is at 2.1 and hadn't seen NG4J before (it's got a lot in common 
with the Session and DatabaseSession interface [1][2]).  I like the idea 
of Jena work being done in this area.  Naming graphs is also used in the 
SOFA and JRDF support in Kowari/TKS - which allows a client/server 
architecture in an RDF API.

The main problem we've had with named graphs is that it can be a pain on 
a machine that has multiple names or names that change over time.  If I 
create a models based on machine names called "http://192.168.10.1/foo" 
and then move to another network and suddenly it's 
"http://10.0.0.42/foo" then all my existing queries stop working.  I now 
prefer URNs for models not URIs and add a level of indirection between 
them (I think this has been mentioned before).

These are links to an external copy of the 1.0.5 javadoc.
[1] 
http://tango.nsdl.cornell.edu/api/kowari/current/org/kowari/server/Session.html
[2] 
http://tango.nsdl.cornell.edu/api/kowari/current/org/kowari/store/DatabaseSession.html
Received on Friday, 10 September 2004 11:32:35 GMT

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