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Re: Added Requirement: Static Constraints

From: Karen Coyle <kcoyle@kcoyle.net>
Date: Thu, 15 Jan 2015 07:45:31 -0800
Message-ID: <54B7E09B.6010506@kcoyle.net>
To: Holger Knublauch <holger@topquadrant.com>, "public-data-shapes-wg@w3.org" <public-data-shapes-wg@w3.org>
Thanks, Holger. As usual, I need to do this "by example" because it's 
quite likely that my vocabulary differs from that of others here.

Use cases: I have data that uses dct:title in various places, and I want 
to say that wherever it is used it can only be used once for each 
subject in my data. Here's some data:

subjectA dce:creator "Somebody" .
subjectA dct:title "Some title" .
subjectA bf:subject http://.... .
subjectB dce:creator "Someone else" .
subjectB dct:title "Another title" .

subjectA dce:creator "Somebody" .
subjectA dct:title "Some title" .
subjectA bf:subject ex:subject1 .
subjectB dce:creator "Someone else" .
subjectB dct:title "Another title" .
subject1 dct:title "A related book" .

That's a pretty stupid example, and the data is more sophisticated than 
that, of course. My questions are:

a) because this data does not use rdf:type (unless inferred, and let's 
say it isn't), does subject "s" constitute a node/graph/shape?
b) substitute "skos:prefLabel" here and a rule that skos:prefLabel can 
occur only once per each "X" (X because I dont know what to call it) - 
is that the same case?
c) is this really a new use case, or a variation on existing ones?


On 1/11/15 3:14 PM, Holger Knublauch wrote:
> Hi Karen,
> thanks for your comment on requirement
> https://www.w3.org/2014/data-shapes/wiki/Requirements#Declarations_of_Property_Min.2FMax_Cardinality
> in which you ask how to represent a constraint such as "there must be
> one instance of classX". While I was responding, I noticed that we did
> not yet have a story about "global" constraints that are evaluated
> independently from specific instances or classes. I propose to call them
> "static constraints" and have added a corresponding requirement:
> https://www.w3.org/2014/data-shapes/wiki/Requirements#Static_Constraints
> Although I am confident that this requirement is important, I had a hard
> time finding motivating User Stories in our current catalog. I would
> therefore encourage you (or anyone else) to write down your requirement
> as a User Story and add a cross-link if you are supportive of the Static
> Constraints requirement.
> Thanks
> Holger

Karen Coyle
kcoyle@kcoyle.net http://kcoyle.net
m: 1-510-435-8234
skype: kcoylenet/+1-510-984-3600
Received on Thursday, 15 January 2015 15:46:01 UTC

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