Re: using classes to control constraints

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On 02/07/2015 07:05 AM, Eric Prud'hommeaux wrote:
> * Peter F. Patel-Schneider <pfpschneider@gmail.com> [2015-02-07
> 06:44-0800]
>> In a discussion about the LDOM Primer on 02/07/2015 01:58 AM, Eric
>> Prud'hommeaux wrote: [...]
>>> "This instance passes/fails this shape" is quite clear. Adding a type
>>> arc is effectively a non-starter for this group; there are too many
>>> people who see that is hampering re-usability of the data.
>> 
>> Do you mean to say that there is no chance that any prominent example
>> of constraints working off types will pass muster?
>> 
>> 
>> I am very strongly in favour of having shapes be different from RDFS
>> classes but I also very strongly believe that a common situation is
>> that constraints are triggered from class membership.  This common
>> situation should be prominent in the working group's documents.
> 
> I'm skeptical that it's a common occurance in sensible modeling, but I'm
> certainly happy to be shown otherwise.

I expect that class attachment is the most common trigger for constraints in
SPIN, but maybe the people from TopQuadrant have some usage figures that
would verify this expectation.

> Its possible that our disagreement stems from different starting
> conditions. Here are mine:
> 
> Much of the value of RDF stems from "serendipitous reuse".

Agreed.

> The prominent examples should use the core shapes language.

I agree that the prominent examples should use the core portion whatever is
produced from the WG.

> Physical laws like area aren't typical of business logic.

Agreed, but this doesn't seem to be relevant to the issue at hand.



Here is what I would expect from the first example in a primer.

1/ There is an ontology for something.  (Let's use bugs.)   The ontology
describes several classes, such as bugs and people, and several properties,
such as state and reporter, all in an open-world setting.

2/ There is some RDF data that uses this ontology, describing one or more
bugs and people.

3/ There is some wording that introduces the notion of verifying that
sufficient information is present so that useful things can be done with the
RDF data.

4/ A set of constraints/shapes are given whose effect is that if the data
correctly validates the bug instances do indeed have sufficient information.
 These constraints/shapes are triggered off the bug class.


I believe that this example satisfies all your desiderata above.

peter





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Received on Saturday, 7 February 2015 16:37:49 UTC