Hi Beppe, If these are RDF Linked Data View “Virtual” Graphs then these are stored in a different Quad Map storage location, see:
http://docs.openlinksw.com/virtuoso/rdfviewquadmapatternsvalueandiriclasses/
But you should be able to delete such graphs wit the “drop graph <graph-name>”
sparql query as indicated in the “Delete RDF Graphs” section of the following
white paper on "Mapping Relational Data to RDF with Virtuoso's RDF Views” :
https://virtuoso.openlinksw.com/whitepapers/relational%20rdf%20views%20mapping.html
Or the indicated alternative SQL method of manually deleting Virtual graphs
(from when drop graph was not supported) can be used ...
Best Regards
Hugh Williams
Professional Services
OpenLink Software, Inc. // http://www.openlinksw.com/
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Universal Data Access, Integration, and Management Technology Providers
> On 6 Mar 2017, at 17:40, Beppe Mazzola <beppemazz...@gmail.com> wrote:
>
> Hi to all
>
> Recently I have sent two e-mails to this forum about two different problems:
>
> • Unable to iterate over a SPARQL query referring to a graph. In a
> stored procedure the iterations over a SPARQL statement result set are not
> executed. See https://sourceforge.net/p/virtuoso/mailman/message/35686416/
> • Unable to delete a graph content Some graphs are impossible to
> delete, despite the deletion commands do not issue any error. See
> https://sourceforge.net/p/virtuoso/mailman/message/35655255/
>
> Now I have found that they are related. Both happen only with RDF graphs
> which content is generated with the R2RML mapping feature using the
> procedures DB.DBA.TTLP() and DB.DBA.R2RML_MAKE_QM_FROM_G() .
>
>
> I would like to know if anybody has ever succeeded to delete a graph
> generated in this way or to iterate over a SPARQL statement referencing to a
> such a graph inside a stored procedure (the same SPARQL statement run
> interactively works).
>
> Who is interested in reproducing the problem below there is what I think
> should allow it.
>
> I use Virtuoso Open Source Edition (multi threaded)
> Version 7.2.4.3217-threads as of Apr 25 2016
> Compiled for Win64 (x86_64-generic-win-64)
>
>
> Thanks!
>
> Cheers
>
> Beppe
>
>
>
> Deletion Problem
> I have executed the basic.sql example given by OpenLink Software about how to
> use R2RML and I see that the generated RDF graph cannot be deleted. At the
> bottom of this e-mail there is the session in which I run the example and the
> graph deletion fails.
>
> Iteration over a SPARQL query
> After executing the basic.sql example the following commands allow to perform
> an iteration on the graph.
>
>
> create procedure R2RML.TEST.try() returns integer
> {
> for (sparql define input:storage ""
> select ?o
> #from <http://localhost:8890/sparql>
> from <http://example.com/>
> where { ?s ?p ?o } LIMIT 5 ) do
> {
> string_to_file ('trashMe.txt', "o"||'\n', -1);
> };
> };
> R2RML.TEST.try();
>
>
>
> In my installation no iteration is performed with these commands. Changing
> with a non-generated graph instead (for example the commented out one) the
> iterations are performed.
>
>
> I have reinstalled Virtuoso Open Source for Windows together with the
> rdb2rdf_dav vad package (from here) before performing the test, in order to
> have an environment unaffected by previous operations.
>
>
>
>
>
> SQL> load .\basic.sql;
> Done. -- 4 msec.
> Done. -- 16 msec.
> Done. -- 0 msec.
> Done. -- 0 msec.
> Done. -- 0 msec.
> STATE MESSAGE
> VARCHAR VARCHAR
> _______________________________________________________________________________
>
> 00000 IRI class <r2rml:virt02-d6310c8f81a31b40880be84617cef62c> has been
> defined (inherited from rdfdf:sql-integer-uri-nullable)
> 00000 Literal class <r2rml:virt02-bf406ba67f39c90ee07c9e8b9f0611ae> has
> been defined (inherited from rdfdf:sql-integer-literal-nullable)
> 00000 Quad storage
> <http://www.openlinksw.com/schemas/virtrdf#DefaultQuadStorage> is flagged as
> being edited
> 00000 Quad map <http://temp/product> has been created and added to the
> <http://www.openlinksw.com/schemas/virtrdf#DefaultQuadStorage>
> 00000 Quad map <sys:qm-0b840fec4c625440d1915a0ae8e5cab9> has been created
> and added to the
> <http://www.openlinksw.com/schemas/virtrdf#DefaultQuadStorage>
> 00000 Quad map <sys:qm-84e7c00e26da8476895ddc0d779d2538> has been created
> and added to the
> <http://www.openlinksw.com/schemas/virtrdf#DefaultQuadStorage>
> 00000 Quad map <sys:qm-60348ca058fc088a9c89f6e10efc15f9> has been created
> and added to the
> <http://www.openlinksw.com/schemas/virtrdf#DefaultQuadStorage>
> 00000 Quad storage
> <http://www.openlinksw.com/schemas/virtrdf#DefaultQuadStorage> is unflagged
> and can be edited by other transactions
> 00000 Transaction committed, SPARQL compiler re-configured
> 00000 9 RDF metadata manipulation operations done
>
> 10 Rows. -- 297 msec.
> SQL>
> SQL>
> SQL> sparql select * from <http://example.com/> where {?s ?p ?o};
>
> s p
> o
> LONG VARCHAR LONG VARCHAR
> LONG VARCHAR
> ___________________________________
>
>
>
> http://example.com/product/1 http://example.com/product#id
> 1
> http://example.com/product/1 http://example.com/product#name
> Virtuoso
> http://example.com/product/1
> http://www.w3.org/1999/02/22-rdf-syntax-ns#type http://example.com/ns#product
>
>
> 3 Rows. -- 16 msec.
>
> SQL>
>
> SQL> SPARQL CLEAR GRAPH <http://example.com/>;
>
> callret-0
>
> LONG VARCHAR
>
> ____________________________________________________________________
>
>
>
> Clear graph <http://example.com/> -- done
>
>
>
> 1 Rows. -- 16 msec.
>
> SQL>
>
> SQL>
>
> SQL> sparql select * from <http://example.com/> where {?s ?p ?o};
>
> s p
> o
> LONG VARCHAR LONG VARCHAR
> LONG VARCHAR
> __________________________________
>
>
>
> http://example.com/product/1 http://example.com/product#id
> 1
> http://example.com/product/1 http://example.com/product#name
> Virtuoso
> http://example.com/product/1
> http://www.w3.org/1999/02/22-rdf-syntax-ns#type http://example.com/ns#product
>
>
> 3 Rows. -- 15 msec.
>
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