Named graph filter

Support
1

Do I need a specific setting in the database properties to be able to filter graphs?

this works:

select distinct *
where { 
    GRAPH ?g {
        ?s ?p ?o
        
    }
}

and returns named graphs

<urn:graph:foaf>
<urn:graph:skos>

but when I ask for a filter for a graph on the list, it just returns nothing:

select distinct ?g
where { 
    GRAPH ?g {
        ?s ?p ?o
        
    }
    FILTER (?g=<urn:graph:foaf>)
}

Any clues why? I tried the stardog studio online and it works there, but doesn't on my local version.

2

No, you shouldn't need anything. What's your Stardog version? Also please post the query plan.

Thanks,
Pavel

3

Server version 7.4.0

From local
Distinct [#1]
`─ Projection(?g) [#1]
   `─ Bind(<urn:graph:foaf> AS ?g) [#1]
      `─ Scan[SPOC](?s, ?p, ?o){<urn:graph:foaf>} [#1]
4

Thanks. We are so far unable to reproduce on a toy data with either 7.4.0 or 7.4.1 candidate. Are you able to share your dataset?

Cheers,
Pavel

5

I basically only have a few ontologies loaded. I loaded foaf and skos ontologies into their own named graphs, no data yet. Regardless of how I set up my database, I seem not to be able to get named graphs out. That is why I was wondering if there was some setting that was conflicting with getting named graphs out.

6

Got it, I was using pystardog to load the database and I was using <urn:graph:skos> to load the data. There <> was causing the trouble. Removed those and it worked.

7

Ah, glad you figured it out!

Best,
Pavel

8

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