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Re: Property Path usage query

From: Steve Harris <steve.harris@garlik.com>
Date: Mon, 13 Aug 2012 11:43:59 +0100
Cc: <public-rdf-dawg-comments@w3.org>
Message-Id: <4B48FC9A-89C0-4FC9-B580-C93EA1097AE0@garlik.com>
To: Nicholas Humfrey <nicholas.humfrey@bbc.co.uk>
Not a formal response, but I think that would require aggregates, e.g.:

SELECT (MIN(?name) AS ?sname)
WHERE {
  <http://example.com/bob> foaf:knows ?person .
  ?person foaf:name ?name .
}
GROUP BY ?person

If you use PPs then you could write foaf:knows/foaf:name, but then you can't express the grouping, as there's an implicit variable in the path expression.

- Steve

On 2012-08-13, at 11:37, Nicholas Humfrey wrote:

> Hello,
> 
> I have a question about what is possible using property paths:
> 
> Given this dataset:
> <http://example.com/bob>    foaf:name  "Bob"  .
> <http://example.com/joe>    foaf:name  "Joe"  .
> <http://example.com/joe>    foaf:name  "Joe Bloggs"  .
> <http://example.com/alice>  foaf:name  "Alice"  .
> <http://example.com/bob>    foaf:knows  <http://example.com/joe>  .
> <http://example.com/bob>    foaf:knows  <http://example.com/alice>  .
> 
> 
> Is it possible to construct a Property Path query that returns a single name
> for each of the people that Bob knows? ie "Joe", "Alice"
> 
> 
> Thanks,
> 
> nick.
> 
> 
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Received on Monday, 13 August 2012 10:44:23 GMT

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