Re: Why not adopt ShEx? (was Re: Enough already)

This group may find interesting the results of a study of various RDF 
validation methods in existence as of 2015:

http://dcevents.dublincore.org/IntConf/dc-2015/paper/view/386/368

The study, which I believe was the basis for a doctoral dissertation, 
used SPARQL rules as a way to unify the comparison of 5 different 
constraint languages, including OWL2, ShEx and SPIN (This was pre-SHACL).

Their conclusion was that each constraint language had some advantages, 
some disadvantages. However, as long as there was a way to test 
equivalency of the constraints, having more than one language was an 
plus, since different communities might have different needs or 
preferences. Their use of SPARQL was as formalism to map between 
languages, and such a formalism does seem to have advantages -- a way to 
know exactly what an expressed constraint is actually constraining, and 
to allow one to run tests across different languages. The languages 
themselves, with the exception of SPIN, were not however based on SPARQL.

The approach of an abstract expression of constraints that can be tested 
with SPARQL (or some other formalism, but SPARQL exists and is known) 
and that can support different implementations is appealing. ShEx and 
SHACL have been tested in one direction, which is that ShEx can be 
translated to SHACL and they can share a test suite. (Someone should 
correct me if I've mis-understood any of this.)

My feeling is that people will have particular development environments 
they they work in, and that it needs to be possible to integrate 
validation into those environments. This means that some folks will work 
closely to SPARQL, some to OWL2, and some will continue to make use of 
validation that is not RDF-specific, like Schematron. Ideally, one 
should be able to move from one environment to the other and know that 
the validation results are equivalent. In the sense that RDF supports 
sharing between communities, it makes sense to also be able to share 
validation rules.

kc



On 12/11/16 9:33 AM, Martynas Jusevičius wrote:
> Sorry, but I see zero advantages of ShEx over SPIN/SPARQL.
>
> Why would I want to lock my software into a new non-standard syntax with
> close to none adoption, when I can simply use the query engine to
> validate constraints?
>
> On Sun, 11 Dec 2016 at 18.26, Gray, Alasdair J G <A.J.G.Gray@hw.ac.uk
> <mailto:A.J.G.Gray@hw.ac.uk>> wrote:
>
>
>>     On 10 Dec 2016, at 11:52, Martynas Jusevičius
>>     <martynas@graphity.org <mailto:martynas@graphity.org>> wrote:
>>
>>     In case of SHACL specifically, I think the problem is that while
>>     SPIN was an elegant concept on top of SPARQL, shoehorning
>>     constraints into a vocabulary is a model mismatch, a little like
>>     putting an ORM on top of RDBMS: it works most of the time, but
>>     there will always be corner cases you cannot hammer out.
>
>     If this is indeed the case, why is the group not building upon the
>     purpose defined ShEx approach?
>
>     Its concise notation makes it very elegant for defining constraints.
>     I have been using it in a tool for almost two years now. The tool is
>     quick and easy to adapt to new sets of constraints by specifying a
>     new ShEx schema.
>
>     I also find its use of exclusive or more naturally fits the
>     requirements I have encountered for constraint specifications.
>
>     Best regards,
>
>     Alasdair
>
>     Alasdair J G Gray
>     Fellow of the Higher Education Academy
>     Assistant Professor in Computer Science,
>     School of Mathematical and Computer Sciences
>     (Athena SWAN Bronze Award)
>     Heriot-Watt University, Edinburgh UK.
>
>     Email: A.J.G.Gray@hw.ac.uk <mailto:A.J.G.Gray@hw.ac.uk>
>     Web: http://www.macs.hw.ac.uk/~ajg33
>     ORCID: http://orcid.org/0000-0002-5711-4872
>     Office: Earl Mountbatten Building 1.39
>     Twitter: @gray_alasdair
>
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-- 
Karen Coyle
kcoyle@kcoyle.net http://kcoyle.net
m: 1-510-435-8234
skype: kcoylenet/+1-510-984-3600

Received on Monday, 12 December 2016 03:51:15 UTC