Re: shapes-ISSUE-91 (hsolbrig): Default Cardinality [SHACL Spec]

I vote -1 to defining optional values for any constraint.

The current design is consistent in its treatment of absent
constraints, namely that they do not lead to any checks. It is
therefore inconsistent to say that if minCount or maxCount are absent
then they are in effect present with some default value. If is
especially inconsistent to assign default values that give a result
different than if the constraints were absent.

-- Arthur


On Sun, Sep 27, 2015 at 1:45 AM, Eric Prud'hommeaux <eric@w3.org> wrote:
> * Holger Knublauch <holger@topquadrant.com> [2015-09-26 18:59+1000]
>> Yes correct. No sh:maxCount triple means it is unlimited. This is
>> consistent with how all other constraints work. The datatype of
>> sh:maxCount is xsd:integer, so a "*" would not work. sh:maxCount=0
>> would mean that no triples are allowed.
>
> Some languages favor readability by defining max as either an unsigned
> integer or the token "*".
>
> http://www.w3.org/TR/xmlschema-1/#element-element
>
>
>> Holger
>>
>>
>> On 9/26/15 4:19 PM, Karen Coyle wrote:
>> >Holger, are you saying that currently there is no way to specify
>> >maxCount = unlimited except to not include maxCount? Presumably
>> >either "maxCardinality = *" or "maxCardinality = 0" would convey
>> >this.
>> >
>> >kc
>> >
>> >On 9/26/15 12:48 AM, Holger Knublauch wrote:
>> >>Hypothetically, if we set the default of sh:maxCount to 1. How would one
>> >>change it to unlimited?
>> >>
>> >>Holger
>> >>
>> >>
>> >>
>> >>On 9/25/15 10:15 PM, Karen Coyle wrote:
>> >>>I think that the cardinality defaults interact with the closed/open
>> >>>graph definition. If the graph is open, then a default of
>> >>>"minCardinality = 0, maxCardinality = *" is pretty close to
>> >>>meaningless. In an open graph, all potential predicates are "optional"
>> >>>unless defined otherwise, and specifying optional predicates does not
>> >>>invoke any useful behavior. In the case of an closed graph,
>> >>>"minCardinality = 0" describes a specific optional predicate.
>> >>>
>> >>>SHACL, if I understand it correctly, describes an open graph by
>> >>>default. This means that only ""minCardinality > 0" can be validated.
>> >>>
>> >>>Although the statement by Holger that "if something is left
>> >>>unspecified then it should count as unconstrained" resonates, I would
>> >>>consider the inclusion of a optional property to be specified, not
>> >>>unspecified.
>> >>>
>> >>>kc
>> >>>
>> >>>On 9/25/15 1:02 AM, Holger Knublauch wrote:
>> >>>>I believe if something is left unspecified then it should count as
>> >>>>unconstrained. So if no sh:minCount or sh:maxCount is given then it
>> >>>>should count as 0..* by default.
>> >>>>
>> >>>>PROPOSAL: Close ISSUE-91 stating that the default interpretations of
>> >>>>sh:minCount and sh:maxCount (and their qualified counterparts) should
>> >>>>remain as currently specified.
>> >>>>
>> >>>>Holger
>> >>>>
>> >>>>PS: A compact syntax may of course use different conventions and
>> >>>>automatically generate the corresponding min/max triples.
>> >>>>
>> >>>>
>> >>>>On 9/25/2015 0:46, RDF Data Shapes Working Group Issue Tracker wrote:
>> >>>>>shapes-ISSUE-91 (hsolbrig): Default Cardinality [SHACL Spec]
>> >>>>>
>> >>>>>http://www.w3.org/2014/data-shapes/track/issues/91
>> >>>>>
>> >>>>>Raised by: Harold Solbrig
>> >>>>>On product: SHACL Spec
>> >>>>>
>> >>>>>The defaults for cardinality in UML are [1..1]  (see:
>> >>>>>MultiplicityElement.lowerBound() and MultiplicityElement.upperBound()
>> >>>>>on page 41 of OMG specification ptc/2013-09-05).  Should these be the
>> >>>>>defaults for mincount and maxcount in Section 3.1.5 of the SHACL
>> >>>>>specification as well?  Currently they are [0..*].
>> >>>>>
>> >>>>>
>> >>>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>
>> >>
>> >>
>> >>
>> >
>>
>>
>
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> -ericP
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Received on Sunday, 27 September 2015 22:18:19 UTC