Hello Mikael, In current version of Virtuoso, the constructor of DELETE acts like any plain constructor so it does not search for appropriate values of variables in the database. This is the first issue. In addition, Virtuoso is quad store, not triple store, and graphs are not entirely separated from each other. When in doubt, be verbose re. graphs in use. Thus I'd recommend to use 'fair' syntax in spirit of 2.d), not 2.c) example of same specification:
PREFIX dc: <http://purl.org/dc/elements/1.1/> PREFIX xsd: <http://www.w3.org/2001/XMLSchema#> DELETE FROM GRAPH <http://example/bookStore> { ?book ?p ?v } WHERE { GRAPH <http://example/bookStore> { { dc:date ?date . FILTER ( ?date < "2000-01-01T00:00:00"^^xsd:dateTime ) ?book ?p ?v } } In common, Virtuoso intentionally reports errors in some cases when other SPARQL implementations silently ignore uninitialized variables. The rationale is that unlike many other implementations Virtuoso allows SPARQL subqueries in SQL queries and Virtuoso/PL stored procedures. In a complicated SQL environment it is much better to stop compilation than to miss unintentional typo in variable name. E.g., if we permit unitialized variables then the following statement will silently delete all data from graph: PREFIX dc: <http://purl.org/dc/elements/1.1/> PREFIX xsd: <http://www.w3.org/2001/XMLSchema#> DELETE FROM GRAPH <http://example/bookStore> { ?bok ?p ?v } WHERE { ?book dc:date ?date . FILTER ( ?date < "2000-01-01T00:00:00"^^xsd:dateTime ) } Moreover, Virtuoso may map relational data to RDF by 'RDF Views' and now we're implementing updateable RDF views so SPARUL statement will be able to write to relational tables, if needed, including tables on remote SQL servers. Thus, instead of removal of all data from RDF graph such query may actually drop all data of a relational table of a business application, repelling IT manager from using SPARUL anymore :) Best Regards, Ivan Mikhailov OpenLink Software. -----Original Message----- From: virtuoso-users-boun...@lists.sourceforge.net [mailto:virtuoso-users-boun...@lists.sourceforge.net] On Behalf Of Mikael Hogqvist Sent: Thursday, July 12, 2007 7:26 PM To: virtuoso-users@lists.sourceforge.net Subject: [Virtuoso-users] SPARUL insert/delete Hi! I'm using the virtuoso SPARUL implementation to manage the RDF-data from remote. I ran into a problem when trying to remove and insert data in a single query which I think is due to the SPARUL implementation in virtuoso. I'm running the example query 2.c) from: http://jena.hpl.hp.com/~afs/SPARQL-Update.html. I added "FROM GRAPH <http://example/bookStore>" since it doesnt work without that. Here is the result from virtuoso: 37000 Error SP031: SPARQL compiler: Variable 'v' is used in the query result set but not assigned SPARQL query: define output:valmode "LONG" PREFIX dc: <http://purl.org/dc/elements/1.1/> PREFIX xsd: <http://www.w3.org/2001/XMLSchema#> DELETE FROM GRAPH <http://example/bookStore> { ?book ?p ?v } WHERE { ?book dc:date ?date . FILTER ( ?date < "2000-01-01T00:00:00"^^xsd:dateTime ) } >From my point of view, it is ok if ?v is not assigned. This should then mean that all triples matching the (?book, ?p)-bindings should be removed independent of the value of the object. Best Regards, Mikael ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Virtuoso-users mailing list Virtuoso-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/virtuoso-users
