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Re: named graphs

From: Patrick Stickler <patrick.stickler@nokia.com>
Date: Mon, 3 May 2004 12:51:01 +0300
Message-Id: <62E95CEA-9CE7-11D8-A824-000A95EAFCEA@nokia.com>
Cc: "Phil Dawes" <pdawes@users.sourceforge.net>, <www-rdf-interest@w3.org>
To: "ext Chris Bizer" <chris@bizer.de>

On Apr 30, 2004, at 14:43, ext Chris Bizer wrote:

> Hi Phil,
>> I'm getting to the point where I need to start including provenance
>> information in response to queries. I was wondering where the whole
>> standardisation process is wrt named graphs.
>> - Does the trix proposal represent current thinking in this field?
> The current status quo of the trix work is described in
> http://lists.w3.org/Archives/Public/www-archive/2004Apr/att-0081/PID- 
> FAFPGYHS-1081860211.pdf
> Beside of TriX, there is also a N3-like syntax for Named Graphs called  
> TriG,
> see:
> http://www.wiwiss.fu-berlin.de/suhl/bizer/TriG/
>>    - e.g. is the standardised model likely to be radically different
>>    to its multiple closed-graphs approach?
>> - Are there any triple stores that support the notion of named
>> graphs internally? (i.e through the api)
> There are no implementations yet, but it is planned to implement Named
> Graphs as an extension to Jena 2 (Jeremy is to one to ask about details
> here).

RDF Gateway by Intellidimension (http://www.intellidimension.com) has  
support for "contexts" which could be easily used to implement named  
(since a named graph is just as easily modeled as a context). The query
language then provides native support for context-specific statements,
as well as context-specific security/access control.

>> - Has there been any work on query languages supporting querying
>> across graphs?
>> e.g.
>> select ?foo, ?bah
>> from <grapha>, <graphb>, <graphc>
>> where (...)

Again, the query language provided with RDF Gateway provides for
exactly this kind of multi-graph queries.

What would be nice to see (and necessary in the long run IMO) would
be a means to specify the target graphs by a sub-query. I.e.

select ?foo, ?bah
from ?graph
where (?graph rdf:type my:TrustedGraph)
and (...)


> There are two query languages for Named Graphs RDFQ and TriQL
> http://www.wiwiss.fu-berlin.de/suhl/bizer/TriQL/  (Both not  
> implemented yet)
> I guess Jeremy, Pat and Patrick might also answer later ...

RDFQ has been a useful "thought experiment" that I would like to have
seen reach a higher stage of maturity in the implementation, but further
development is at the moment, and probably for the summer, "on ice".



> Chris


Patrick Stickler
Nokia, Finland
Received on Monday, 3 May 2004 05:51:50 UTC

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