Data loaded but sparql query returns zero rows

Support
1

I've tried to laod the trig file via studio - no luck. I used the command line and it shows 90 triples loaded besides the db icon.

$ ./stardog data add MyDB pp_project_mydb.trig

The following sparql returns zero rows:

SELECT ?s ?p ?o
WHERE
{ ?s ?p ?o
} LIMIT 50 OFFSET 0
  • Am I doing something wrong?

Thanks,
Radu

2

Hey Radu,

Is your data in the trig file in the default graph? The query is over the default graph.

3

i doubt it is in default graph ... it is some sort of skos scheme - but i have added the "skos" archtype to db and restarted it.

4

You have several options here:

  • Include a graph variable in your query from { graph ?g { ?s ?p ?o } }
  • Query over all graphs from <tag:stardog:api:context:all> { ?s ?p ?o }
    These queries will include matches from not only the default graph, but also named graphs.
5

Thank you that worked

6

Jess - I had the query working but with latest studio ugrade - command history is gone :frowning: - and my select is no longer working against all (virtual) graphs

SELECT * {
    GRAPH <tag:stardog:api:context:all>  {  ?s ?p ?o } 
}

Is the above close enough?

Thanks,
Radu

7

You should include the special graph IRI in the dataset specification:

select * from <tag:stardog:api:context:all> {
?s ?p ?o
}
8

ok that worked - thank you - but bringing too much info now ...

How do I query for a single virtual graph that was created like:

PREFIX : <http://sample/docs/>
MAPPING <urn:docs>
FROM GraphQL {
    documents{
...
9

You can query the virtual graph using a graph clause:

GRAPH <virtual://documents> {
...
}
10

I am getting zero rows back for this query:

SELECT * {
    GRAPH <virtual://documents>  {  ?s ?p ?o } 
}

pymongo find brings back 10 documents

11

What command did you run to add the virtual graph?

12

I have first used this:

 ./stardog-admin virtual add --overwrite --format SMS2 mongodb.properties documents.sms

Then modified the VG via studio. I have also tried to revert it - successfully - but still zero rows back

13

From docs:

Name of the configuration file without the extension will be the name of the virtual graph.

So virtual graph name with be mongodb.