W3C home > Mailing lists > Public > public-vocabs@w3.org > April 2014

Re: Discovering the full schema.org vocabulary (Was: Re: Schema.org site updates: Added RDFa and JSON-LD incoming properties)

From: Kingsley Idehen <kidehen@openlinksw.com>
Date: Sun, 06 Apr 2014 11:42:01 -0400
Message-ID: <534175C9.2010003@openlinksw.com>
To: public-vocabs@w3.org
On 4/6/14 3:35 AM, Niklas Lindström wrote:
> Hi Kingsley,
>
> On Sat, Apr 5, 2014 at 7:27 PM, Kingsley Idehen 
> <kidehen@openlinksw.com <mailto:kidehen@openlinksw.com>> wrote:
>
>     On 4/5/14 5:04 AM, Niklas Lindström wrote:
>>
>>         For me, I would think that each term might reference the
>>         vocabulary document somehow (perhaps rel=describedBy?). It
>>         would also be useful if going to http://schema.org/ would
>>         somehow allow discovery of the vocabulary.
>>
>>
>>     I agree, that would be nice. I'm sure rdfs:isDefinedBy [1] is the
>>     right property for that. :)
>
>     An rdfs:isDefinedBy relation associates Properties and Classes
>     with the vocabulary in which they are defined.
>
>     An wdrs:describedby (equivalentPropertyOf xhv:describedBy and
>     inversePropertyOf xhv:describes) relation associates Properties
>     and Classes with a Vocabulary document (e.g.,
>     <http://schema.org/docs/schema_org_rdfa.html>
>     <http://schema.org/docs/schema_org_rdfa.html>) that is comprised
>     of statements describing the aforementioned Properties and Classes.
>
>
> Yes, that is true. I was rather vague in my statement about the 
> "right" property here. I was thinking more of linking the classes and 
> properties (in the dedicated pages describing them) to the vocabulary 
> itself. I am not sure whether the URI for that is 
> <http://schema.org/>, or another resource represented by the RDFa 
> serialization. Given the status of the latter as a "mere" 
> representation, I do agree that describedby seems more correct. But 
> since schema.org <http://schema.org> in general avoids the 
> distinction, what I had in mind was more along the lines of this 
> (expressed in TriG):
>
>     graph <http://schema.org/Thing> {
>         <http://schema.org/Thing> rdfs:isDefinedBy <http://schema.org/> .
>     }
>     graph <http://schema.org/> {
>         <http://schema.org/> rdfs:seeAlso 
> <http://schema.org/docs/schema_org_rdfa.html> .
>     }
>
> (In general when I write scripts processing multiple vocabularies 
> together, I look for rdfs:isDefinedBy. Rather often though, I need to 
> revert that to string inspection of the term identifiers. Even for 
> OWL. So I might be wishing for too much here.)
>
>     Ideally, you want to use both relations due to the fact that an
>     Ontology is one entity, a Document comprised of what constitutes
>     an Ontology is another entity [1].
>
>
> Ideally, I would agree. :) But even this distinction was under debate 
> elsewhere some years ago [2] (ah, pedantic-web..). And since 
> schema.org <http://schema.org> does "shadow" documents with what their 
> URIs formally denote (which I accept), I was thinking of avoiding that 
> debate by aiming for "what is meant" rather than "what describes 
> what". But I surely know this is hard to do, and this question does 
> raise the distinction. Hopefully not to the point of debating 
> httpRange-14 (let's not go there here), but to determine a useful 
> means for describing and discovering schema.org <http://schema.org> 
> the vocabulary.
>
> (Given how this goes I might pull out of the debate, since I get 
> really nervous when I say httpRange-14 in public like this. It's like 
> saying "Candyman".)
>
> Cheers,
> Niklas
>
> [2]: 
> https://groups.google.com/forum/#!msg/pedantic-web/RZ6kxlAVIy8/8r_JE4gVXFAJ 
> <https://groups.google.com/forum/#%21msg/pedantic-web/RZ6kxlAVIy8/8r_JE4gVXFAJ>

Since schema.org is document scoped, re., entity denotation granularity, 
it can use wdrs:describedby and xhv:describes based relations [1] for 
associating classes, properties with the documents (e.g., 
<http://schema.org/docs/schema_org_rdfa.html> )  in which they are 
described.

[1] https://www.iana.org/assignments/link-relations/link-relations.xhtml 
-- covers describedby and describes based relations.

-- 

Regards,

Kingsley Idehen	
Founder & CEO
OpenLink Software
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Received on Sunday, 6 April 2014 15:42:23 UTC

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