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Re: SKOS concept scheme URIs as values for constraints

From: Phil Archer <phila@w3.org>
Date: Fri, 7 Aug 2015 17:58:01 +0100
To: Martynas Jusevičius <martynas@graphity.org>, Arnaud Le Hors <lehors@us.ibm.com>, Holger Knublauch <holger@topquadrant.com>
Cc: public-data-shapes-wg@w3.org, "public-rdf-shapes@w3.org" <public-rdf-shapes@w3.org>
Message-ID: <55C4E399.1020508@w3.org>
OK Martynas, but does that imply the HTTP GET I'm after as well?

On 07/08/2015 17:55, Martynas Jusevičius wrote:
> Phil,
>
> why are you basing your design on the namespace URI? I think a more
> semantic way would be to allow all values of ?concept, where ?concept
> rdfs:isDefinedBy ?ontology, and ?ontology is the vocabulary you want to use.
>
>
> Martynas
> graphityhq.com
>
> On Fri 7 Aug 2015 at 18:48 Phil Archer <phila@w3.org> wrote:
>
>> Thanks for the replies everyone.
>>
>> Hmm... templates, special code, DIY... Meh. In short, the use case is
>> not covered out of the box.
>>
>> To be useful, I'd expect the validator to go and fetch the SKOS concept
>> scheme and check that the value of a property is valid. So I guess the
>> questions would be:
>>
>> 1. Does the URI given as the value of a property dereference?
>> 2. Does the type of that resource match what I expect (is it typed as a
>> SKOS Concept in this case).
>>
>> Of course, that's a heavy burden, I well understand that, and the burden
>> may be more than is needed in many cases, and too much in others, but
>> authoritative lists of allowed values are not uncommon.
>>
>> If this is out of scope for the work, OK, that's my answer. If the
>> answer is "you can bolt something on the side that does it" then, well,
>> I'd likely not bother with the bolt and just do it myself anyway - which
>> kind of defeats the object.
>>
>> Karen's Use Case 37 does indeed seem very similar and, yes, SHACL has
>> regEx matching, enumerated lists and so on, so a lot of what I'm asking
>> can be done - and that may be sufficient (or that may have to be
>> sufficient), but without fetching the authoritative list of allowed
>> values from an external source, the issue of synchronising will always
>> come up.
>>
>> I should indeed have some test data imminently, if it's wanted.
>>
>> Thanks
>>
>> Phil.
>>
>> PS. I'm very likely to join the f2f in Lille next month as I'll be
>> passing through on my way home from Brussels. Looking forward to
>> catching up with the wider work of the group.
>>
>> On 05/08/2015 01:01, Holger Knublauch wrote:
>>> This is correct and thanks for highlighting this. I wanted to be brief
>>> and could elaborate or even implement the template as an example. I was
>>> hoping that my statement "using a template" would have been sufficiently
>>> clear, but maybe it wasn't. Yes, there needs to be at least one person
>>> on the planet, knowledgeable of SPARQL and SHACL, who needed this
>>> feature to cast it into a template and publish it for everyone else to
>> use.
>>>
>>> (BTW I later noticed that the original requirement may have been about
>>> checking for the presence of URIs in a certain named graph. In that
>>> case, the SPARQL GRAPH keyword could be used, assuming the named graphs
>>> are present in the same dataset, or SERVICE for external graphs. There
>>> are all kinds of variations here, which is why my inclination is to
>>> leave this as an opportunity for third-party templates, not the core
>>> language.)
>>>
>>> Regards,
>>> Holger
>>>
>>>
>>> On 8/5/2015 9:29, Arnaud Le Hors wrote:
>>>> Holger,
>>>>
>>>> I think we ought to clarify that what you present here isn't all it
>>>> takes because it relies on having shx:allowedValueNamespaces defined
>>>> somewhere, presumably using the SPARQL extension.
>>>>
>>>> I know you wrote "an end-user syntax" and the implication is that some
>>>> advanced-user has defined such a template for the end-user but we need
>>>> to be careful not to set the wrong expectation.
>>>>
>>>> Regards.
>>>> --
>>>> Arnaud  Le Hors - Senior Technical Staff Member, Open Web Technologies
>>>> - IBM Software Group
>>>>
>>>>
>>>> Holger Knublauch <holger@topquadrant.com> wrote on 08/03/2015 03:29:13
>>>> PM:
>>>>
>>>>> From: Holger Knublauch <holger@topquadrant.com>
>>>>> To: public-data-shapes-wg@w3.org, "public-rdf-shapes@w3.org"
>>>>> <public-rdf-shapes@w3.org>
>>>>> Date: 08/03/2015 03:30 PM
>>>>> Subject: Re: SKOS concept scheme URIs as values for constraints
>>>>>
>>>>> This could be represented in SHACL using a template, with an end-user
>>>>> syntax such as
>>>>>
>>>>> ex:MyShape
>>>>>       a sh:Shape ;
>>>>>       sh:property [
>>>>>           a shx:AllowedValueNamespacesConstraint ;
>>>>>           sh:predicate ps:siteDesignation ;
>>>>>           shx:allowedValueNamespaces (
>>>>> "http://inspire.ec.europa.eu/codelist/DesignationValue/" ) ;
>>>>>           sh:valueClass skos:Concept ;
>>>>>       ] .
>>>>>
>>>>> In the above scenario I am assuming that the algorithm will check that
>>>>> all values of the given property must be URIs starting with one of the
>>>>> enumerated strings (using STRSTARTS in SPARQL). It would not go to the
>>>>> web to check whether there is actually a Graph at that namespace -
>> this
>>>>> would be outside of what SPARQL can do right now.
>>>>>
>>>>> I cannot comment on whether this particular pattern should become part
>>>>> of the Core vocabulary too, but the whole point of the extension
>>>>> mechanism is to allow anyone to represent and publish their own
>>>> favorite
>>>>> constraint design patterns, so that they don't rely on the choices
>> made
>>>>> by a particular working group in the year 2015.
>>>>>
>>>>> Holger
>>>>>
>>>>>
>>>>>
>>>>> On 8/4/2015 5:39, Karen Coyle wrote:
>>>>>> Phil,
>>>>>>
>>>>>> Thanks for bringing this up. I thought that I had covered this in
>> use
>>>>>> case #34 [1], and at one point I asked if all of these criteria were
>>>>>> met by the requirements and I was assured that they were. This is a
>>>>>> key use case for the cultural heritage community, so if there are
>> any
>>>>>> doubts that these requirements can be met we need to address this.
>>>>>> Perhaps the was to resolve this is to provide test cases. There seem
>>>>>> to be some functional versions of SHACL that could be used to test
>>>>>> this, if I'm not mistaken. Would you be able to provide some test
>>>> data?
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> kc
>>>>>> [1]
>>>>>> http://w3c.github.io/data-shapes/data-shapes-ucr/#uc37-defining-
>>>>> allowed-required-values
>>>>>>
>>>>>> On 8/3/15 9:48 AM, Phil Archer wrote:
>>>>>>> Hi,
>>>>>>>
>>>>>>> I've had an opportunity to take a look at the SHACL work today and
>> I
>>>>>>> notice one of the use cases looks set to be missed - although
>>>> only just.
>>>>>>>
>>>>>>> The UCR doc includes the one about self-describing Linked Data
>>>> [1] which
>>>>>>> talks about the value of a property being a skos:Concept. Are you
>>>>>>> considering making this a little tougher, i.e. that the value of
>>>> a given
>>>>>>> property is a concept defined in a specific scheme?
>>>>>>>
>>>>>>> I see that SHACL allows the enumeration of values [2], but I want
>>>> to be
>>>>>>> able to say "any value from the SKOS Concept scheme at <foo>". It
>>>> looks
>>>>>>> like SHACL won't support that?
>>>>>>>
>>>>>>> Use Case: INSPIRE
>>>>>>>
>>>>>>> INSPIRE [0] - the European Union's obligatory set of standards for
>>>>>>> environmental and geospatial data - has a handy registry of SKOS
>>>> concept
>>>>>>> schemes [3]. In one of my projects, I've been working on creating
>>>> RDF
>>>>>>> vocabularies that are compatible with the INSPIRE data model,
>>>> such as
>>>>>>> the one about protected sites [4]. That has a property
>>>>>>> ps:siteDesignation for which the range is defined as skos:Concept
>>>> but
>>>>>>> really what it should say is:
>>>>>>>
>>>>>>> the value of this property should be a skos:Concept in the scheme
>> at
>>>>>>> http://inspire.ec.europa.eu/codelist/DesignationValue/.
>>>>>>>
>>>>>>> It would be inappropriate to enumerate the concepts in that concept
>>>>>>> scheme (there are 6 of them) since it is under a different
>>>>>>> organisation's change control.
>>>>>>>
>>>>>>> I recognise that this leads to the possibility that a graph that is
>>>>>>> valid today may become invalid if the INSPIRE Registry were to be
>>>>>>> amended but that's a management task for the European Commission to
>>>>>>> worry about (i.e. the people responsible for the INSPIRE data
>>>> model) and
>>>>>>> they would need to be mindful of such situations which would occur
>>>>>>> whether we were talking about RDF graphs or dollops of GML, so I
>>>> don't
>>>>>>> think that's a show stopper here.
>>>>>>>
>>>>>>> WDYT?
>>>>>>>
>>>>>>> Phil.
>>>>>>>
>>>>>>>
>>>>>>> [0] http://inspire.ec.europa.eu/
>>>>>>>
>>>>>>> [1]
>>>>>>> http://w3c.github.io/data-shapes/data-shapes-ucr/#uc28-self-
>>>>> describing-linked-data-resources
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> [2]
>>>>>>> http://w3c.github.io/data-shapes/shacl/
>>>>> #AbstractAllowedValuesPropertyConstraint
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> [3] http://inspire.ec.europa.eu/registry/
>>>>>>>
>>>>>>> [4] http://www.w3.org/2015/03/inspire/ps
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>>
>>
>> --
>>
>>
>> Phil Archer
>> W3C Data Activity Lead
>> http://www.w3.org/2013/data/
>>
>> http://philarcher.org
>> +44 (0)7887 767755
>> @philarcher1
>>
>>
>

-- 


Phil Archer
W3C Data Activity Lead
http://www.w3.org/2013/data/

http://philarcher.org
+44 (0)7887 767755
@philarcher1
Received on Friday, 7 August 2015 16:57:59 UTC

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