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Re: Fwd: namespace versioning (Dublin Core) use case for DAWG?

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Mon, 06 Sep 2004 13:39:28 +0100
Message-ID: <413C5A80.7080101@hp.com>
To: Tom Adams <tom@tucanatech.com>
CC: DAWG public list <public-rdf-dawg@w3.org>

The UC requirements on disjunction allows this to be expressed.

I am not in favour of special mechansim syntax for handling the special 
case of alternative predicates if we have the requirement for general 
disjunction.  We could have special syntax to generate the same query - 
personally, I don't see a need from this one case.  Are there others?

DCMI have choosen to have completely different URIs for dc11:titile and 
dc10:title which coudlbe because the defintion of title has been 
improved in 1.1 making it different from title in 1.0.

The "temporarily assume" is a query premise and is an update on the 
query target so, if the taget is a shared resource, needs locking or 
transaction or something to isolate the query.

There can be many appraoches to versioning so I don't think we are 
helping to supporting one approach and not others at this stage.


Tom Adams wrote:

>  From the comments list for our perusal.
> Begin forwarded message:
>> Resent-From: public-rdf-dawg-comments@w3.org
>> From: Dan Brickley <danbri@w3.org>
>> Date: 3 September 2004 1:35:02 PM
>> To: public-rdf-dawg-comments@w3.org
>> Cc: public-swbp-wg@w3.org
>> Subject: namespace versioning (Dublin Core) use case for DAWG?
>> (sent to DAWG feedback list, cc: Best Practices WG)
>> Hi
>> Apologies if this is already covered and I missed it.
>> I'd like DAWG to consider a use case in which a client application wants
>> all the "Dublin Core titles and descriptions" of some object, eg.
>> Danbri's weblog(s), and doesn't care at all which concrete Dublin Core
>> namespace is used.
>> ie.
>>     http://purl.org/dc/elements/1.0/
>>     http://purl.org/dc/elements/1.1/
>> This is a practical issue w/ DC deployment. I'm ignoring for now the
>> additional mess around upper/lowercase. Assume that we see dc10:title
>> and dc11:title in data, that the semantics are pretty much the same but
>> that the schemas aren't explicitly/formally mapped using RDFS or OWL
>> constructs.
>> A couple of approaches leap to mind: 'or'ing, vs. query-specific
>> assumptions, ie. allowing the query to say "Well, let's temporarily
>> assume that dc1:title is a subproperty of dc2:title and vice-versa,
>> ...".
>> Both approaches have their issues (eg. 'or'ing both dc:title and
>> dc:description in a larger query might be hairy),
>> but my sense is that there is a real problem when similar
>> namespaces where new URIs have been assigned
>> despite modest differences in meaning. If DAWG ends up deciding not to
>> create technology that soothes these issues, the Best Practices WG might
>> consider making reference to querying issues when it discusses best
>> practice for Vocabulary Management and versioning.
>> cheers,
>> Dan
>> ps. Eric P, perhaps you could comment on how this is dealt with in
>> Annotea's treatment of Dublin Core 1.0 vs 1.1?
Received on Monday, 6 September 2004 12:39:56 UTC

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