Subject: [urn] multiple URNs for the same resource (CREF11)

From: Peter Saint-Andre - &yet <[email-masked]>
Date: Wed, 11 Mar 2015 20:24:57 -0600

Section 6 states:

    With regard to global uniqueness, using different NIDs for different
    collections of identifiers ensures that no two URNs will be the same
    for different resources, since each collection is required to
    uniquely assign each identifier.  However, a single resource can have
    more than one URN assigned to it for different purposes (e.g., some
    numbers might be valid identifiers in two different identifier
    systems, where the namespace identifier differentiates between the
    resulting URNs).  Subject to other constraints, such as those imposed
    by the URI syntax [RFC3986], the rules of the URN scheme are intended
    to allow preserving the normal and natural form of identifiers
    specified elsewhere and treated as URN namespaces.

CREF11 poses a question for the WG:

Ted suggested adding a concrete example, "as this seems likely to be 
open to confusion.  The RFC 5031 emergency services may provide one 
(e.g. urn:service:counseling.mental-health and 
urn:service:counseling.suicide may be the same resource), but any 
concrete example would likely be an improvement."  Is that example ok? 
Would anyone like to suggest other text or an additional example?]]

I think that example is fine - we might want to clearly describe that 
the "resource" here is the same service number or dial string as 
explained in the introduction to RFC 5031.

Peter

-- 
Peter Saint-Andre
https://andyet.com/

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From: Juha Hakala <[email-masked]>
Date: Fri, 13 Mar 2015 13:04:37 +0200

Hello,

The most common reason for a single resource having more than one 
identifier is the overlap in the scopes of identifier systems.

For instance, a book can have both ISBN and ISSN if the book has been 
published in monograph series (and the series has an ISSN). Also, 
multivolume books like The Lord of the Rings have one ISBN for the 
entire work, and in addition each volume has its own ISBN. Note that the 
results of resolving these identifiers will differ: in the former 
example ISSN would typically resolve to metadata about the monograph 
series, and in the latter example ISBN of the entire work will retrieve 
e.g. metadata about all volumes.

If we need to give an example of identifier overlap, I prefer using 
urn:issn and urn:isbn instead of RFC 5031 -based one since ISBN and ISSN 
are better known and more widely used than the identifier system defined 
in RFC 5031.

Actionable identifiers add another dimension to this. A DOI the 
publisher has assigned to the article will only resolve to the copy the 
publisher has in its own repository, and it is possible that the life 
span of the DOI will not exceed that of the publisher. Therefore the 
national library which gets the article via legal deposit may assign 
e.g. a URN:NBN to it, in order to be able to control the resolution 
process (and, also, to make sure that the persistent identifier used 
will remain actionable even if the publisher goes out of business). As 
an example of this, a Swiss article published in German may get three 
persistent identifiers: DOI by the publisher, and URN:NBNs by German and 
Swiss national libraries, which will both have a legal deposit copy of 
the text.

Juha

-- 

  Juha Hakala
  Senior advisor

  The National Library of Finland
  Library Network Services
  P.O.Box 26 (Teollisuuskatu 23)
  FIN-00014 Helsinki University
  Tel. +358 9 191 44293
  Mobile +358 50 3827678

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From: Peter Saint-Andre - &yet <[email-masked]>
Date: Mon, 16 Mar 2015 14:31:43 -0600

On 3/13/15 5:04 AM, Juha Hakala wrote:
> entire work, and in addition each volume has its own ISBN.

Yes, that is a good example, too.

> Note that the

I see no harm in giving more than one example, although I agree with you 
about the commonality of ISBNISSN vs. RFC 5031 identifiers.

Peter

-- 
Peter Saint-Andre
https://andyet.com/