W3C home > Mailing lists > Public > public-data-shapes-wg@w3.org > January 2016

Re: ISSUE-95 Discussions

From: Karen Coyle <kcoyle@kcoyle.net>
Date: Mon, 25 Jan 2016 07:22:38 -0800
To: Irene Polikoff <irene@topquadrant.com>, public-data-shapes-wg@w3.org
Message-ID: <56A63DBE.6030809@kcoyle.net>

On 1/24/16 9:22 PM, Irene Polikoff wrote:
> Agree, it is certainly used by W3C vocabularies. But the industry work
> doesnąt seem to follow this practice.
> For example:
> schema.org had an outdated version that uses this property, but in a
> totally different way:
> <rdf:Description rdf:about="http://schema.org/Action˛>
> <rdf:type rdf:resource="http://www.w3.org/2000/01/rdf-schema#Class˛/>
> <rdfs:label xml:lang="en">Action</rdfs:label>
> <rdfs:comment xml:lang="en˛/>
> <rdfs:subClassOf rdf:resource="http://schema.org/Thing˛/>
> <rdfs:isDefinedBy rdf:resource="http://schema.org/Action˛/>
> </rdf:Description>

No, that's the right way to use it, AFAIK. Of course, schema is a bit 
odd in many ways...

> FIBO doesnąt use it at all.
> AGROVAC doesnąt use it.

I believe that is because AGROVOC is a SKOS vocabulary, and 
skos:inScheme takes the place of rdfs:isDefinedBy. (Although I suppose 
you could use both.)

> Life Sciences vocabularies donąt seem to use it.
> I canąt recall seeing anyone in the industry use it when developing their
> own ontologies.

Right. It's probably not needed if you don't openly share your 
data/ontology. We do use it in Dublin Core, and it undoubtedly has some 
bleed-through from library practices where declaring "authority" for 
data and practices is important. For data that will be openly shared 
with anyone, those anyone's - at least some of them - will want to know 
what are the bona fides for any particular property, and to be able to 
locate the original definition. If your data won't exit your enterprise 
system and you don't allow strangers to come along and add links, then 
this isn't an issue.


> Just to be clear, I am not advocating not using this convention for SHACL.
> I am simply wondering what is the motivation for this practice and why it
> is so rarely followed outside of the standard models published by W3C.
> Irene Polikoff
> On 1/24/16, 11:47 PM, "Karen Coyle" <kcoyle@kcoyle.net> wrote:
>> I was hoping that the Linked Open Vocabulary project could help answer
>> this as they provide states on property use across over 550 vocabs.
>> However, their search system is broken.
>> So instead I looked at the list of W3C vocabularies,[1] and only one
>> (something called "Earl") did not use rdfs:isDefinedBy. All of the
>> others did, and that list is:
>> I looked at the Open Annotation vocabulary,[2] which I know is close to
>> being completed, and it, too, uses rdfs:isDefinedBy.
>> I think this shows that this *is* a W3C best practice.
>> kc
>> [1] https://www.w3.org/standards/techs/rdfvocabs#w3c_all
>> [2] http://www.openannotation.org/spec/core/20130208/
>> On 1/24/16 4:07 PM, Irene Polikoff wrote:
>>> There is no harm in using rdfs:isDefinedBy and may be some value in it.
>>> I am not totally sure what it is though.
>>> In practice, it is very rarely used for instances. Because it is not
>>> practical, I guess, to always carry this extra triple. It is sometimes
>>> used for schemas, but certainly far from universally used. So, from the
>>> software perspective, it canąt be relied on ­ unless the person who
>>> writes software has full control over what schemas they use and how they
>>> look like.
>>> As for living with other vocabularies in a triple store, this wouldn't
>>> require rdfs:isDefinedBy. The best practice is to have each vocabulary
>>> as a separate named graph and then one could always query for its
>>> content in SPARQL using FROM or FROM GRAPH.
>>> Irene Polikoff, CEO
>>> TopQuadrant, Inc. www.topquadrant.com <http://www.topquadrant.com/>
>>> *Technology providers making enterprise information meaningful*
>>> Blogs ‹ http://www.topquadrant.com/the-semantic-ecosystems-journal/,
>>> http://www.topquadrant.com/composing-the-semantic-web/
>>> LinkedIn ‹ https://www.linkedin.com/company/topquadrant
>>> Twitter - https://twitter.com/topquadrant
>>> From: Holger Knublauch <holger@topquadrant.com
>>> <mailto:holger@topquadrant.com>>
>>> Date: Sunday, January 24, 2016 at 6:45 PM
>>> To: "public-data-shapes-wg@w3.org <mailto:public-data-shapes-wg@w3.org>"
>>> <public-data-shapes-wg@w3.org <mailto:public-data-shapes-wg@w3.org>>
>>> Subject: Re: ISSUE-95 Discussions
>>> Resent-From: <public-data-shapes-wg@w3.org
>>> <mailto:public-data-shapes-wg@w3.org>>
>>> Resent-Date: Sun, 24 Jan 2016 23:46:09 +0000
>>>> No, rdfs:isDefinedBy is the way to link an RDF term with its ontology.
>>>> My XSLT relies on that. It also lets vocab information live in a
>>>> triple store with other vocabs. You can then get all the terms for a
>>>> given vocab using a SPARQL query.
>>> Again, I don't like carrying around extra triples just for the sake of a
>>> particular XSLT implementation. These triples are trivial to
>>> auto-generate at any point in time. Having said this, for the purpose of
>>> making progress I will try to edit them in (although I expect this to be
>>> error-prone). Better would be to leave them out for now and put them
>>> back in on the day prior to publication.
>> --
>> 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 Monday, 25 January 2016 15:23:09 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 19:30:29 UTC