Re: [dotNetRDF-bugs] empty result bug

[Rob V. <rv...@do...>]

You have not shown your code so we have no way of knowing how you are
executing your query and so what may/may not be going wrong

Most likely you have loaded your data into a named graph (perhaps
unintentionally) but your query only queries the default graph I.e. the
results are correct because you aren't querying what you think you are.  A
query like the following will tell you exactly what data is in what graph:

SELECT * WHERE { GRAPH ?g { ?s ?p ?o } UNION { ?s ?p ?o } }

If you get no results then you are querying an empty dataset, if you get
results with values for ?g then your data is indeed in a named graph so your
query which only looks in the default graph can never match anything.

I would recommend that you refer to the documentation of Querying with
SPARQL [1] and Debugging SPARQL Queries [2] which discuss common errors like
this and how to debug query behaviour.

If you are still having issues then you will need to show your exact code to
reproduce this as otherwise we cannot help you further.

Rob

[1] 
https://bitbucket.org/dotnetrdf/dotnetrdf/wiki/UserGuide/Querying%20with%20S
PARQL
[2] 
https://bitbucket.org/dotnetrdf/dotnetrdf/wiki/HowTo/Debug%20SPARQL%20Querie
s.wiki#!debugging-sparql-queries

From:  Wadea Hijjawi <csw...@gm...>
Reply-To:  dotNetRDF Bug Report tracking and resolution
<dot...@li...>
Date:  Tuesday, 18 November 2014 09:58
To:  <dot...@li...>
Subject:  [dotNetRDF-bugs] empty result bug

> Dear sir,,,
> I have tried dotnetrdf user toolkit and tried to  use the following simple
> turtle file  :  
>  
> # filename: ex002.ttl
>  
> @prefix ab: <http://learningsparql.com/ns/addressbook#> .
>  
> ab:richard ab:homeTel "(229) 276-5135" .
> ab:richard ab:email   "ric...@ho..." .
>  
> ab:cindy ab:homeTel "(245) 646-5488" .
> ab:cindy ab:email   "ci...@gm..." .
>  
> ab:craig ab:homeTel "(194) 966-1505" .
> ab:craig ab:email   "cra...@ya..." .
> ab:craig ab:email   "c....@us..." .
>  
>  
> and  the following  query  :
> # filename: ex003.rq
>  
> PREFIX ab: <http://learningsparql.com/ns/addressbook#>
>  
> SELECT ?craigEmail
> WHERE
> { ab:craig ab:email ?craigEmail . }
>  
>  
> It must return two results  ,  but it returns an empty result
> 
> -- 
> 
> 
> Wadea Asad Hijjawi
> 
> ASP.NET <http://asp.net/>  & Oracle DB Developer
> 
> Civil Service  Bureau
> 
> 06-5604181  Ext:289
> 
> 
> 
> 
> 
> 
> 
> 
> 
>  
> 
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