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

[Will D. <ma...@wi...>]

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 
<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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