- From: Irene Polikoff <irene@topquadrant.com>
- Date: Wed, 22 Jun 2016 17:36:07 -0400
- To: kcoyle@kcoyle.net
- Cc: public-data-shapes-wg@w3.org
I don't really know what min and maxInstanceCount are. Aren't they a pretty new proposal and not in the spec yet? If so, then deciding that they should be in the spec and their meaning is work to be done. Or had the voting on it happened already? I was talking solely about the general nature of scopes and constraints. Scopes identify focus nodes. Constraints specify conditions focus nodes must satisfy. Scopes select focus nodes, not triples. This is true in general, irrespective of a particular constraint. Sent from my iPhone > On Jun 22, 2016, at 4:56 PM, Karen Coyle <kcoyle@kcoyle.net> wrote: > > I would really like to hear from folks who are not part of TopBraid, because it appears that there is a kind of "secret language of twins" where things communicate to Holger and Irene even though they are opaque to others. No where in ISSUE 168 is what Irene says below explained. In fact, the issue seems to have some magic involved with min and maxInstanceCount, which are not defined anywhere in the issue. I really don't care if it makes sense to Holger and Irene if it isn't communicated clearly in the spec. The meaning of these new elements are not defined in the proposal, so the proposal needs to be clarified before it can be considered. What are min/maxInstanceCount, what is the formality that describes them, and exactly where throughout SHACL can they be used? > > kc > > >> On 6/22/16 8:51 AM, Irene Polikoff wrote: >> >> The definition of a class is that it is a resource of type (transitively) >> rdfs:Class. There can be classes that have zero instances. This doesn’t >> change the fact that they are classes. I could also imagine a constraint >> that would dictate that a certain class should have no instances in the >> graph. This means that if one wanted to check if something was a class, >> they would look for its own type statement, not if it has instances. >> >> However, scopes don’t really make such checks. They only selects nodes >> that are to be evaluated against constrains. In this case, the constraint >> will check if ex:A is the object of rdf:type triple. >> >> If the constraint sets minInstanceCount to 1 or higher and ex:A is not an >> object of rdf:type triple, there will be a violation. If constraint sets >> minInstanceCount to exactly 0 or 0 or more and there are no rdf:type >> triples ex:A is an object to, no violation is raised. I believe this is >> what expected. >> >> >> Irene >> >> >> >> >> >>> On 6/22/16, 10:10 AM, "Karen Coyle" <kcoyle@kcoyle.net> wrote: >>> >>> Thank you, Holger, that answers my question. But it also confirms that >>> this solution is unrelated (aka "orthogonal") to the request for a way >>> "How to constrain number of instances of a class in a graph" as this >>> issue is called, because this does not constrain the number of instances >>> of a class in a graph. If this is presented as a solution, there must be >>> an explanation of how it differs from the requirement as stated. This >>> sets as scope node any IRI provided. Nothing here checks that "ex:A" is >>> the object of rdf:type. >>> >>> kc >>> >>>> On 6/21/16 3:38 PM, Holger Knublauch wrote: >>>> >>>> >>>>> On 22/06/2016 4:57, Karen Coyle wrote: >>>>> OK, let me persist here. We have the suggested code example of: >>>>> >>>>> ex:MyShape >>>>> a sh:Shape ; >>>>> sh:scopeNode schema:FlightReservation ; >>>>> sh:constraint [ >>>>> sh:minInstanceCount 1 ; >>>>> sh:maxInstanceCount 1 ; >>>>> ] . >>>>> >>>>> I'm going to abstract this as: >>>>> >>>>> ex:MyShape >>>>> a sh:Shape ; >>>>> sh:scopeNode ex:A ; >>>>> sh:constraint [ >>>>> sh:minInstanceCount 1 ; >>>>> sh:maxInstanceCount 1 ; >>>>> ] . >>>>> >>>>> Given the examples below, which of these are in scope for >>>>> "sh:scopeNode ex:A" >>>>> >>>>> ex:A ex:B ex:C . >>>>> >>>>> ex:B ex:A ex:C . >>>>> >>>>> ex:B ex:C ex:A . >>>> >>>> Just ex:A is in scope. sh:scopeNode is independent of any triples, i.e. >>>> even if a node appears in no triple, it would still be in scope. This >>>> also means that sh:scopeNode is orthogonal to a node being subject, >>>> predicate or object. This is only relevant to sh:scopeProperty and >>>> sh:scopeInverseProperty. >>>> >>>> Holger >>>> >>>> >>>>> >>>>> >>>>> kc >>>>> >>>>>> On 6/17/16 4:43 PM, Irene Polikoff wrote: >>>>>> Also, I don¹t think the below is right. I thought that the scope >>>>>> identifies nodes. Not subject or objects, just nodes. >>>>>> >>>>>> Then, constraints specify conditions or patterns to be specified. >>>>>> Focus >>>>>> nodes can be either an object or a subject in these patterns. For >>>>>> example, >>>>>> when a PropertyConstraint is used focus nodes are subjects, but an >>>>>> InverseProperty constraint specifically allows specifying patterns >>>>>> where >>>>>> focus nodes are objects. >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>> On 6/17/16, 1:10 PM, "Karen Coyle" <kcoyle@kcoyle.net> wrote: >>>>>>> >>>>>>> nd scopeNode binds to the subject of a >>>>>>> triple, AFAI can determine. >>> >>> -- >>> Karen Coyle >>> kcoyle@kcoyle.net http://kcoyle.net >>> m: 1-510-435-8234 >>> skype: kcoylenet/+1-510-984-3600 > > -- > Karen Coyle > kcoyle@kcoyle.net http://kcoyle.net > m: 1-510-435-8234 > skype: kcoylenet/+1-510-984-3600
Received on Wednesday, 22 June 2016 21:36:46 UTC