- From: Andy Seaborne <andy.seaborne@epimorphics.com>
- Date: Tue, 01 Mar 2011 17:35:18 +0000
- To: nathan@webr3.org
- CC: RDF WG <public-rdf-wg@w3.org>
On 01/03/11 17:23, Nathan wrote:
> Andy Seaborne wrote:
>> On 01/03/11 16:41, Nathan wrote:
>>> actually ^ may be better.. such that
>>>
>>> :a :b :c .
>>>
>>> could be written as:
>>>
>>> :c ^:b :a .
>>>
>>> meaning
>>>
>>> :c [ owl:inverseOf :b ] :a .
>>
>> meaning there is a there is bnode in the predicate position.
>>
>>>
>>> meaning:
>>>
>>> :a :b :c .
>>>
>>
>> SPARQL has:
>>
>> :c ^:b :a .
>>
>> meaning
>>
>> :a :b :c
>>
>> reverses subject and object. The matching process really does swap
>> subject and object.
>>
>> http://www.w3.org/TR/sparql11-query/#propertypaths
>
> wouldn't that require subjects as literals?
Yes.
http://www.w3.org/TR/rdf-sparql-query/#sparqlTriplePatterns
They are legal in SPARQL 1.0; they just never match.
In a practical sense, it's unavoidable in explaining:
Data:
:x :p "abc" .
Query pattern:
{ ?x :p ?o .
?o :q ?z <--- ****
}
or
{ ?x :p ?o .
OPTIONAL {?o :q ?z } <--- ****
}
Andy
Received on Tuesday, 1 March 2011 17:35:56 UTC