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Re: RDF API 1.0 Draft / signing RDF content

From: Gabe Beged-Dov <begeddov@jfinity.com>
Date: Mon, 06 Dec 1999 15:43:46 -0800
Message-ID: <384C4A32.2C766171@jfinity.com>
To: Sergey Melnik <melnik@DB.Stanford.EDU>
CC: RDF Interest Group <www-rdf-interest@w3.org>
Sergey Melnik wrote:

> Gabe Beged-Dov wrote:
> > The first question is related to the interaction between the model being
> > "closed" and the generation of the signature. Should the concept of the
> > model being open vs. closed be part of the API?
> Could you reformulate this question? If this is what you are asking
> about: the model URI is recomputed whenever triples are added or removed
> from the model. ...Uups, just found a bug, this is currently not being
> done in the code...

I'm thinking that there may be many benefits to making the state of the model
(open/closed) an explicit part of the processing model. When a model is open,
you can add triples to it using the low level add/remove calls.  Once it is
closed you would not be able to modify the model.  Until the model is closed,
it doesn't have a signature. The act of closing a model is a significant
event in the model's lifecycle that involves generating the signature for the
model and potentially for all the noname resources in the model.

The set and query operations might only make sense on closed models.  This
potentially allows many simplifications and optimizations in the processing
approach.  It looks like you may be going in the direction of side-effect
free composition with the SetModel interface, I.e. a functional programming
style where you can trace back the set operations and operands that
correspond to a particular model.  This  is easier to do with read-only
models that don't require rewriting pointers and such.

> Noname URI generation is a syntax related issue. However, it will arise
> no matter what kind of XML-based syntax we take. So what do you think
> about (1)-(3)?

I assume (with hand-waving) that we can find some graph algorithm for
identifying the minimal subgraph that is rooted at the noname resource.  If
this subgraph occurs in multiple places then I would feel comfortable with
using the same ID.  If we are using a content based ID then it needs to be in
synch with the contents (issue 3).  If you go with the explicit closing
approach, then the model can't change once the URI for the model and nonames
are bound.

Received on Monday, 6 December 1999 18:59:38 UTC

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