Re: [urn] I-D Action: draft-saintandre-urn-example-00

Keith Moore <moore@network-heretics.com> Fri, 17 August 2012 14:09 UTC

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Date: Fri, 17 Aug 2012 10:09:04 -0400
From: Keith Moore <moore@network-heretics.com>
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To: Julian Reschke <julian.reschke@gmx.de>
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Subject: Re: [urn] I-D Action: draft-saintandre-urn-example-00
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On 08/17/2012 09:08 AM, Julian Reschke wrote:
> On 2012-08-17 14:17, Keith Moore wrote
>> That's not a very useful definition for determining whether a URN is
>> appropriate.  But my point is that a URN should name _something_.
>
> My understanding is that if you can give it a name (URI/URN), it is 
> "something".

Yes, but you can coin names without binding them to anything, or without 
being clear about what you're naming.
>> In addition, it needs to be clear what is being named by the URN.
>> Otherwise there's no way to ensure persistence of the binding between
>> the URN and the resource.
>
> Given a UUID, there's no way to know *what* is being named without 
> additional information. How is that a problem in practice, if all you 
> need is a unique identifier?

URNs aren't merely unique; the binding between the URN and the resource 
named is expected to be persistent.   By declaring something to be a 
URN, you're making both assertions.

UUIDs are unique (by definition), but just because you create a UUID for 
something doesn't mean you're committing to making the binding between 
the UUID and that something persistent.   It follows that not every UUID 
should be considered to be suitable for use in a UUID URN.

(naming is tricky and extremely subtle)

Keith