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Re: [Graphs] Proposal: RDF Datasets

From: Nathan <nathan@webr3.org>
Date: Tue, 08 Mar 2011 16:32:52 +0000
Message-ID: <4D765A34.7030705@webr3.org>
To: Ivan Herman <ivan@w3.org>
CC: Richard Cyganiak <richard@cyganiak.de>, antoine.zimmermann@insa-lyon.fr, RDF Working Group WG <public-rdf-wg@w3.org>
Ivan Herman wrote:
> If we have the concept of a (<u>,G) for naming a, hm, named graph, g-box, or whatever, that is fine. You and Antonie are arguing on the semantics of _datasets_; I am still not convinced that this discussion should happen in the first place!

I'm increasingly wondering whether there's a bit of a false start here, 
you see if we have (<u>,G), and G refers to a g-box, then it's a set of 
values over time, which you can't serialize, hence why you refer to it 
by name, which means you only refer to <u>, and there's no need, or way, 
to actually write (<u>,G) in a serialization.

So for g-boxes, we just have URIs, and talk about them by URI as we do 
today (no change).

As for talking about g-snaps, well there are only really three choices:
  - quoted graph
  - graph literal
  - g-text in a literal
the distinction between the former two I'm unsure.

So for the g-snap case, perhaps all that's needed is a temporary name 
which is a property of the serialization, so one can write:

   temp { :a :b :c }
   temp :created "2011...." .

Which itself raises a few questions about what that means, does "temp" 
alias a literal, or?

Finally, and perhaps most pertinent to this thread, is that there seems 
to be a need for a standardized way of getting a snapshot of a rdf 
dataset, for use with quad stores and the like, quite different from 
extending RDF, but rather something to cover backup/restore and use case 
of moving triples/quads/graphs between stores. Does the RDF model need 
to cater for that? I can't see how, but it's a very valid/real use case 
that does need handled.

So, I guess I'm now feeling that the "named g-box" case is simply <u>, 
the store backup/interchange/snapshot case is just constrained trig to 
example 3 [1], or nquads - and as for g-snaps, well that would need 
worked out, either nothing (just make sure web resources are persistent 
and don't change), graph literals (doesn't need any change afaict), or 
quoted graphs.

Best,

Nathan
Received on Tuesday, 8 March 2011 16:34:46 UTC

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