[Dev] Introduction; Shimmer Prototype Database

Uche Ogbuji uche.ogbuji at fourthought.com
Wed Nov 13 20:25:08 PST 2002


> Someone, maybe Sean Palmer, has written about using quints instead of 
> triples, to also deal with the "sez who?" meta-attribute. (But I'm a 
> super-beginner at RDF...)

This is an old concept in RDF, and one which unfortunately never seems to make 
it into any specs  :-(

This is exactly what I was talking about in my latest post about how 4Suite 
does this using scopes, which are arbitrary URI connected to each statement.

We built in scopes because we ran into the need for them in practice, and a 
lot of people here have rehashed some of the cases where they are important.

One warning: scopes are not enough for clean N-ary relationships in general.  
I prefer to use blank nodes for those.

Anyways, If Chandler goes with the intriguing idea of maintaining RDF triples 
as Python object/attribute structures, then squeezing in 
scopes/contexts/whatever will not be so easy.  It would probably require 
computed attributes, which would result in a performance hit and a 
complication of the persistence model.

Maybe plain old Python quintuples are the ticket.  This is what the 4Suite 
memory model uses (well, actually sextuples).


-- 
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