Re: link from ns/shacl to ns/shacl-shacl

I do agree that for many data models there will be one very strong 
"default" shapes graph. However, there was quite some resistance against 
that idea within the WG leading to the point where even sh:targetClass 
statements were frowned upon by some, because they may tie classes too 
much to shapes.

In the case of shacl.ttl the shacl-shacl.ttl is one candidate default 
shapes graph (albeit only for SHACL Core). But I expect that many shapes 
graphs/ontologies will owl:import the shacl.ttl file.

As soon as any file has a transitive owl:imports relation to that file, 
it would mean that any locally defined sh:shapesGraph triples would be 
augmented by that automatic sh:shapesGraph triple. We should be prepared 
for a future in which some people will mix shape, class and data 
definitions all in the same owl:imports closure. So assuming someone has 
a data graph "mypersons" which owl:imports "personontology" and this has 
a sh:shapesGraph link, then these shapes would apply to all data graphs 
that use that ontology. Even worse, there might be a lot of unnecessary 
churn with the same shapes being validated over and over again.

While I have no experience with using sh:shapesGraph "in the wild" yet, 
I think I would prefer to reserve sh:shapesGraph for the cases in which 
a data graph ("instances") points at a shapes graph. The SHACL.ttl file 
contains classes, so it does not really fall into that category. So yes, 
I believe there may be cases that need further discussion and it might 
be more prudent to select another property for this particular case.

How urgent is this decision? I would suggest we put it on the agenda for 
Wednesday.

Holger


On 10/04/2017 13:44, Sandro Hawke wrote:
> Tim was explicit that rdfs:seeAlso wouldn't be good enough, since he 
> wants machines to able to do the importing.
>
> He may not have thought through all the implications, though. What 
> kinds of unpredictable things might happen, do you think?  I suppose 
> it make make some systems validate all their shapes, when that isn't 
> needed.
>
>       -- Sandro
>
>
> On 04/09/2017 10:56 PM, Holger Knublauch wrote:
>> I think sh:shapesGraph would be an option here:
>>
>>     https://www.w3.org/TR/shacl/#sh-shapes-graph
>>
>> However, given that the shacl namespace may be imported into a wide 
>> variety of use cases and thus the potential wide implications of 
>> adding such a triple are unpredictable right now, what about just 
>> rdfs:seeAlso?
>>
>> Holger
>>
>>
>> On 10/04/2017 12:21, Sandro Hawke wrote:
>>> TimBL asked us to put a machine readable link from the SHACL 
>>> namespace document (https://www.w3.org/ns/shacl) to the SHACL 
>>> document which can be used to validate documents written using that 
>>> namespace (https://www.w3.org/ns/shacl-shacl).   This seems like the 
>>> kind of link that would be generally useful, even if only as a rough 
>>> default.  Obviously in many cases, one namespace would be 
>>> appropriately used in lots of different shapes.  But in some cases 
>>> (eg SHACL) where there's a sensible default, it'd be nice for the 
>>> machines to be able to find it.   So, has anyone made such a 
>>> predicate?    If not, is there a reason not to make it up now, as a 
>>> non-rec-track extension?
>>>
>>>      -- Sandro
>>>
>>>
>>
>>
>
>

Received on Monday, 10 April 2017 04:23:35 UTC