- From: Henry Story <henry.story@gmail.com>
- Date: Thu, 1 Jul 2010 16:46:45 +0200
- To: Kingsley Idehen <kidehen@openlinksw.com>
- Cc: Yves Raimond <yves.raimond@gmail.com>, 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>
On 1 Jul 2010, at 16:35, Kingsley Idehen wrote:
> Yves Raimond wrote:
>> Hello Kingsley!
>>
>>
>> [snip]
>>
>>
>>> 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?
>
> bif:contains is a function/magic predicate scoped to Literal Objects.
>
> <people> != "people".
>
> What am I missing?
Why do you think it is magic? Such a relation makes complete sense.
Given that is is a relation between literals it can be tested without needing
to look at the world. Just like an math:isgreaterThan relation ...
In fact I wonder how much SPARQL could be simplified by thinking of things this
way. Could one perhaps get rid of the FILTER( ) clause?
In any case RDF Semantics does, I believe,
allow literals in subject position. It is just that many many syntaxes
don't allow that to be expressed,
But there is nothing you can do to stop that happening semantically. A URI or bnode
can just be names for strings.
And as for it requiring a change to the infrastructure of your DB, it is not clear that
it immediately does, since you can alwasy rewrite
"father" containsLetters 6 .
as
[] owl:sameAs "father";
containsLetters 6 .
Henry
> --
>
> 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 14:47:32 UTC