[Versa] More on literal queries

[Michael Olson]

On Sep 3, 2005, at 8:31 AM, Chimezie Ogbuji wrote:

> I had to sleep on this one.
>
>
>>
>> "some string value"
>>
>> should only return a result if there exists a literal in the form of:
>>
>> "some string value"
>> or
>> "some string value"@some_language
>> or
>> "some string value"^^xsd:string
>>
>> ??
>
> I'm not sure, because it renders this query useless:
>
> typ(rss:Item) |- rss:title -> contains('Versa')
>
> Especially if the rdf store is like so:
>
> _:a rdf:type rss:Item
> _:a rss:title "Versa references"
> _:a rss:title "Versa specifications"
>
> I think you should still be able to 'create' strings (in the query
> space) for reference in filters especially

I agree.  See the new spec (did anyone get this?), it covers this  
(though maybe not really clear).  There is a difference between a  
literal, and a literal query.

I thought of it more in the case of "concat('a','b')"

The difference is

" 'foo' "

Is a literal query, where the results is a set only if the literal  
exists in the DB and

" contains('foo') "

Is just a literal with no additional processing.


Mike
------------------------------------------------------------------------ 
-----------------
Mike Olson                                                Principal  
Consultant
mike.olson at fourthought.com                +1 720 253 4662
Fourthought, Inc.                                       
http://Fourthought.com
PO Box 270590,                                       http://4Suite.org
Louisville, CO 80027-5009, USA
XML strategy, XML tools, knowledge management