[Dev] 4Suite RDF and ZODB

Uche Ogbuji uche.ogbuji at fourthought.com
Wed Nov 13 11:50:58 PST 2002


> On Tue, 2002-11-05 at 11:38, Uche Ogbuji wrote:
> > 
> > My main worry about this is that it seems RDFLib does 
> > not provide some sort of context/scope extension to RDF.  We've found this to 
> > be essential in 4Suite, and very important for practical RDF apps.
> 
> Uche,
> 
> Could you elaborate please?

Sorry.  I'm catching up on things, and I only have a moment to respond  :-(

RDF defines a big graph, but provides no native way to set context within the 
graph.  One example of where this can be useful is for attribution.  
Therefore, you might want to mark all statements gleaned from one particular 
RDF document.  There are others areas where context is important, and, in 
general, the more open and extensible the RDF model is to be, the more useful 
it is to be able to organize it into contexts.  I believe (and hope) Chandler 
will have a rich and broad range of RDF data, and thus I think we'll run into 
the need to associate statements with metainformation.

BTW, for anyone wondering, RDF reification is *not* a solution to this 
problem.  Actually, RDF reification is completely broken, and I think even the 
RDF Core working group is moving away from it.

4Suite supports contexts by allowing one to assign an arbitrary URI to any 
statement.  In effect, a statement isn't a mere triple, but rather a quad:

subject
predicate
object
scope (context)

(Actually, we also have an object data type field for each statement, making 
it a quintuple)


-- 
Uche Ogbuji                                    Fourthought, Inc.
http://uche.ogbuji.net    http://4Suite.org    http://fourthought.com
Python&XML column: 2. Introducing PyXML - http://www.xml.com/pub/a/2002/09/25/p
y.html
The Past, Present and Future of Web Services 1 - http://www.webservices.org/ind
ex.php/article/articleview/663/1/24/
The Past, Present and Future of Web Services 2 - 'http://www.webservices.org/in
dex.php/article/articleview/679/1/24/
Serenity through markup - http://adtmag.com/article.asp?id=6807
Tip: Using generators for XML processing - http://www-106.ibm.com/developerwork
s/xml/library/x-tipgenr.html





More information about the Dev mailing list