[redland-dev] Question about virtuoso storage

Slava Kravchenko slava.kravchenko at gmail.com
Mon Aug 6 11:45:06 EDT 2012


Hello!

I'm trying to use virtuoso storage for Redland, but creating a new
storage with "librdf_new_storage" fails:

  storage = librdf_new_storage(rdf_world, "virtuoso", "db1",
"dsn='VOS',user='cordawyn',password='secret'");
  ...

  librdf error - storage 'db1' not found

I have Virtuoso Open-Source 6.1 running at a local machine (checked it
via the web interface), unixodbc-2.2.14 and librdf0-1.0.14 (all
running on Ubuntu 12.04, x64). "VOS" DSN is available, as reported by
"odbcinst -q -s", the user credentials are correct.

What am I doing wrong? Could it be that librdf is not compiled with
odbc support? "ldd" does not report any dependencies on *odbc*, but
perhaps there shouldn't be any in that list?

<rant>
I'm new to Virtuoso and don't understand what "storage name" (3rd
argument of librdf_new_storage) means. The descriptions at librdf.org
and virtuoso.openlinksw.com (which seem to be just slightly modified
copies) don't help much, sorry ;-) And those extra options (that are
never used in the examples, as far as I can see) just add to the
confusion: I mean "database" and "host". Okay, they are sort of
intuitive, but they're never used in the examples, and the examples
still "work". Also, the example at virtuoso.openlinksw.com says:

  storage=librdf_new_storage(world, "virtuoso", "http://red3",
"dsn='Remote Virtuoso',user='demo',password='demo'");

so... storage name is "http://red3"? What would be the "host" option then?
</rant>


On a somewhat related note, samples at virtuoso.openlinksw.com don't work:

  rdfproc -r xml -t "user='dba',password='dba',dsn='VOS'" gr query
sparql - "SELECT * WHERE { ?s ?p ?o }"

  rdfproc: invalid argument `xml' for `-r / --results'
  Try 'rdfproc -r / --results help' for a list of valid query result formats
  Try `rdfproc -h / --help' for more information.

  rdfproc -r help

  rdfproc: Valid query result formats are:
    xml                   SPARQL XML Query Results
    json                  SPARQL JSON Query Results
    table                 Table
    csv                   Comma Separated Values (CSV)
    tsv                   Tab Separated Values (TSV)
    html                  HTML Table
    turtle                Turtle Query Results
    rdfxml                RDF/XML Query Results

Could anyone help?

Thank you!

Slava Kravchenko


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