W3C home > Mailing lists > Public > public-lod@w3.org > March 2010

Re: National Identification Number URIs ( NIN URIs )

From: Bernhard Schandl <bernhard.schandl@univie.ac.at>
Date: Tue, 9 Mar 2010 10:12:12 +0100
Cc: Hugh Glaser <hg@ecs.soton.ac.uk>, Kingsley Idehen <kidehen@openlinksw.com>, Aldo Bucchi <aldo.bucchi@gmail.com>, Linked Data community <public-lod@w3.org>
Message-Id: <E221FAFF-547D-48C8-8744-8A8AE4E1F9D8@univie.ac.at>
To: Peter Ansell <ansell.peter@gmail.com>

> It is a good thing that the subject URI is an HTTP URI available from
> your server but that is only the start of the story. The rest of the
> story needs other servers to give your data more context.
>>> In your example the fact that there
>>> is a link can only be figured out using some external service that
>>> knows about both data sources.
>> Sure. Before I can add a link to any data set, I have to detect it using some heuristics. Shared URN/DOI/... identifiers seem a valid approach for this -- think of ISBN numbers.
> Sharing identifiers is a good idea, but it isn't Linked Data as yet...

I'm talking of the *preconditions* for linking data, based on shared identifiers. And once I have these identifiers, why not publish them alongside the dereferenceable URIs.

>>> If your server was Linked Data and not
>>> just an HTTP URI based RDF database then it would link out using HTTP
>>> URI's and both servers could be directly explored without some
>>> external service.
>> Once the link has been detected, I can of course add it to both data sets. Well, the owner of the datasets can.
> This is Linked Data, when the dataset owners discover the mutual
> references and link out from their HTTP URI's to the other datasets

Why only the dataset owners? A third party that is aware of both data sets is enabled to discover these links, too.

> It was enabled by sharing the property, and then having
> others discover it. Just sharing the URN property isn't Linked Data as
> people have no way of resolving the URN that is referenced to more
> information.

Again, it's a precondition to link data. 

> It could also have been shared in another way using Inverse Functional
> Properties (IFP) so that the URN scheme need not have been created.

The URN schema for ISBN already exists [1], and several others exist (e.g., SWIFT [2]), why should we throw them away?

[1] <http://www.faqs.org/rfcs/rfc3187.html>
[2] <http://www.faqs.org/rfcs/rfc3615.html>

> There is no automatic HTTP based way of knowing which datasets may
> have relevant links in either case,

One could use indices to find other occurrences of the same URN. When they are linked via owl:sameAs, the linking can be fully automatized.

> so serving up the statements on
> your dataset is very useful for discovery, I wasn't meaning to say
> that was a bad thing. Just emphasising the full story for Linked Data.

I got that :-) 

My point is simply that not *every* URI in a Linked Data context needs to be dereferenceable. When there are established URN schemes in place (like it is the case for ISBN numbers), why not reuse them instead of packing them in a literal (is there a datatype for ISBN numbers?) and publish them to simplify linking for others? This seems to make more sense to me than only relying on URN-to-HTTPURI mappings, which I can still do, as long as I publish the "original" identifier in its "native" URN form.

Received on Tuesday, 9 March 2010 09:14:47 UTC

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