SPARQL Error: [OpenLink][Virtuoso iODBC Driver][Virtuoso Server]SQ074: Line 19: SP030: SPARQL compiler, line 8: Undefined namespace prefix at 'qb' before '.'

[k00ni]

That is an issue based on an email, maybe its author can contribute directly using Github.

He wrote:

when i go to the CubeViz: Analyze DataCube menu option I get the following error:

EMERG (0): Erfurt_Store_Adapter_Exception: SPARQL Error: 
[OpenLink][Virtuoso iODBC Driver][Virtuoso Server]SQ074: Line 19: SP030: SPARQL 
compiler, line 8: Undefined namespace prefix at 'qb' before '.' () in query:

SELECT DISTINCT ?element

FROM <http://ns.ontowiki.net/SysOnt/>
FROM <http://ns.ontowiki.net/SysBase/>
WHERE {
                    ?element a qb:Observation .
                    ?element qb:dataSet ?dataset .
                    ?element ?dimension ?dimelement .
                    ?element ?measure ?value .
                    ?dataset a qb:DataSet .
                    ?dataset qb:structure ?datastructuredefintion .
                    ?dimensionspecification a qb:ComponentSpecification .
                    ?dimensionpecification qb:dimension ?dimension .
                    ?measurespecification a qb:ComponentSpecification .
                    ?measurespecification qb:measure ?measure .
                }  
-> /var/www/libraries/Erfurt/library/Erfurt/Store/Adapter/Virtuoso.php@1060

Of the error message, I am concerned with the escape characters (<) replacing the angle brackets < > in the FROM statements. I get this error both from the Docker build and from the Makefile on a manual LAMP stack for CubeViz. I see from the GitHub repository for a fix Aug 11, 2015 - but I am still getting the error.

[k00ni]

@GeorgesAlkhouri: Could you please check, if you get the same error in your CubeViz-Docker?

[GeorgesAlkhouri]

Yes, this is the same exception we talked about a few month ago. I looked for the issue but i didn't find one. Have you written one?

[k00ni]

Ah ok, i forgot. Can you check, if you can fix it quickly (< 30 min)?

[GeorgesAlkhouri]

The crashing line of code:

https://github.com/AKSW/cubeviz.ontowiki/blob/master/CubevizController.php#L104

The query string is not escaped. This is may be an approach to solve the issue. We will look into it, but it will take a while until we've got time.