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Re: Subjects as Literals, [was Re: The Ordered List Ontology]

From: Kingsley Idehen <kidehen@openlinksw.com>
Date: Thu, 01 Jul 2010 12:42:16 -0400
Message-ID: <4C2CC568.7060604@openlinksw.com>
To: Yves Raimond <yves.raimond@gmail.com>
CC: nathan@webr3.org, Pat Hayes <phayes@ihmc.us>, Toby Inkster <tai@g5n.co.uk>, Dan Brickley <danbri@danbri.org>, Linked Data community <public-lod@w3.org>, Semantic Web <semantic-web@w3.org>
Yves Raimond wrote:
> Hello!
>
>   
>>>> IMHO an emphatic NO.
>>>>
>>>> RDF is about constructing structured descriptions where "Subjects" have
>>>> Identifiers in the form of Name References (which may or many resolve to
>>>> Structured Representations of Referents carried or borne by Descriptor
>>>> Docs/Resources). An "Identifier" != Literal.
>>>>
>>>> If you are in a situation where you can't or don't want to mint an HTTP
>>>> based Name, simply use a URN, it does the job.
>>>>
>>>>         
>>> It does look like you're already using literal subjects in OpenLink
>>> Virtuoso though:
>>>
>>> http://docs.openlinksw.com/virtuoso/rdfsparql.html
>>>
>>> SQL>SELECT *
>>> FROM <people>
>>> WHERE
>>>  {
>>>    ?s foaf:Name ?name . ?name bif:contains "'rich*'".
>>>  }
>>>
>>> Best,
>>> y
>>>
>>>
>>>       
>> Were is the Literal Subject in the query above?
>>     
>
> ?name is a literal. And it is used as a subject.
>   

Yves,

Here's why its deemed magic/function/unreal predicate (a function 
selectively working on literal data associated with the URI):

1. http://bit.ly/cQJTWQ -- SPARQL Query Results Page
2. http://bit.ly/acQc4u -- Actual SPARQL Query

There isn't an actual Literal Subject in the Virtuoso RDF DBMS. The 
RDF_QUAD Table  explicitly has Column "S" set to type IRI.

Here is the actual SQL DML for RDF_QUAD:

create table "DB"."DBA"."RDF_QUAD"
(
  "P" IRI_ID,
  "S" IRI_ID,
  "O" ANY,
  "G" IRI_ID,
  PRIMARY KEY ("P", "S", "O", "G")
);


Kingsley


> Best,
> y
>
>   
>> bif:contains is a function/magic predicate scoped to Literal Objects.
>>
>> <people> != "people".
>>
>> What am I missing?
>>
>> --
>>
>> Regards,
>>
>> Kingsley Idehen       President & CEO OpenLink Software     Web:
>> http://www.openlinksw.com
>> Weblog: http://www.openlinksw.com/blog/~kidehen
>> Twitter/Identi.ca: kidehen
>>
>>
>>
>>
>>
>>     
>
>   


-- 

Regards,

Kingsley Idehen	      
President & CEO 
OpenLink Software     
Web: http://www.openlinksw.com
Weblog: http://www.openlinksw.com/blog/~kidehen
Twitter/Identi.ca: kidehen 
Received on Thursday, 1 July 2010 16:42:54 UTC

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