Re: [Rdfapi-php-interest] SPARQL OPTIONAL error

[Sergey C. <rdf...@an...>]

Thanks, Will, I'll give it a shot!

          Sergey


On Thu, Aug 14, 2008 at 6:06 AM, Will Daniels <ma...@wi...>wrote:

>  This sounds like a bug I filed back in March (fix provided) though I
> don't remember the details precisely now to confirm 100% that it's the same
> issue:
>
>
> http://sourceforge.net/tracker/index.php?func=detail&aid=1928579&group_id=63257&atid=503361
>
> Unfortunately, the bugs do not appear to be attended to. If anybody can and
> wants to grant me access to the svn, I'd be happy to fix a few.
>
> Regards,
> Will
>
> Sergey Chernyshev wrote:
>
> It looks like RAP is having a significant issue with handling OPTIONAL
> blocks - when variable from mandatory part is also used within OPTIONAL
> block and non-optional part of the query matches nothing, OPTIONAL block
> still gets executed as if there was no mandatory part of the query.
>
> For example, query like this:
> *PREFIX dc: <http://purl.org/dc/elements/1.1/>*
> *PREFIX foaf: <http://xmlns.com/foaf/0.1/>*
> *SELECT ?blog, ?title WHERE {*
>  *<http://www.sergeychernyshev.com/sergey> foaf:weblog ?blog .*
> *OPTIONAL { ?blog dc:title ?title}*
>  *}*
>
> ran against http://www.sergeychernyshev.com/sergey.rdf (where foaf:weblog
> triple exists) works fine and returns one entry with defined ?blog and empty
> ?title.
>
> But query
> *PREFIX dc: <http://purl.org/dc/elements/1.1/>*
> *PREFIX foaf: <http://xmlns.com/foaf/0.1/>*
> *SELECT ?blog, ?title WHERE {*
>  *<http://www.w3.org/People/Berners-Lee/card#i> foaf:weblog ?blog .*
> *OPTIONAL { ?blog dc:title ?title}*
>  *}*
>  ran against http://www.sergeychernyshev.com/profile/tests/timbl.rdf(where no foaf:weblog triples exist) returns ?blog variables bound to all
> subjects that have dc:title properties as if this query was ran
> *PREFIX dc: <http://purl.org/dc/elements/1.1/>*
> *PREFIX foaf: <http://xmlns.com/foaf/0.1/>*
> *SELECT ?blog, ?title WHERE {*
>  *OPTIONAL { ?blog dc:title ?title}*
>  *}*
>
> I don't even know how to approach this! Will appreciate any help.
>
> Thank you,
>
>           Sergey
>
>
>  --
> Sergey Chernyshev
> http://www.sergeychernyshev.com/
>
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-- 
Sergey Chernyshev
http://www.sergeychernyshev.com/