clerezza-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Reto Bachmann-Gmür <r...@apache.org>
Subject Re: Querying named graphs do not give the expected results
Date Wed, 08 May 2013 07:19:41 GMT
Hi Minto

On Stanbol I've noticed that some graphs do not appear in
TcManager.listTripleColletions. It might have to do something with an
invalid URI used as graph named. In your example it seems to that you're
nor using correct URIRefs. Could you try if it makes a difference using
real uuid-uris?

Cheers,
Reto


On Mon, May 6, 2013 at 1:29 PM, Minto van der Sluis <minto@xup.nl> wrote:

> Hi folks,
>
> Not sure whether it is my (in)ability to write Sparql queries or
> something odd is going  on. But I am having some trouble with querying
> specific named graphs.
>
> To give some context before showing the queries. I have a situation
> where I have 2 named graphs:
>   1) Index named <http://digimelding.nl/AStore/stamIndex> containing
> references to other named graphs.
>   2) A named graph <7e72ff00-48f1-11e2-bcfd-0800200c9a66> containing
> actual data. The graph name is a UUID.
>
> Querying the first gives expected results. But when querying the second
> I do not get the results I expect.
>
> Query 1: Show all named graphs with actual content(triples).
>  SELECT distinct ?g
>   WHERE {
>     GRAPH ?g {
>       ?s ?p ?o .
>     }
>   }
>
>   Results in:
>   +------------------------------------------+
>   | g                                        |
>   +------------------------------------------+
>   | <7e72ff00-48f1-11e2-bcfd-0800200c9a66>   |
>   | <http://digimelding.nl/AStore/stamIndex> |
>   +------------------------------------------+
>
> Query 2: To show the total number of triples present in both named graphs:
>  SELECT (COUNT(?s) as ?numberOfTriples)
>   WHERE {
>     GRAPH ?g {
>       ?s ?p ?o .
>     }
>   }
>
>   Results in:
>   +--------------------------------------------------+
>   | numberOfTriples                                  |
>   +--------------------------------------------------+
>   | "29"^^<http://www.w3.org/2001/XMLSchema#integer> |
>   +--------------------------------------------------+
>
> Query 3: Get the number of triples present in the index graph.
>   SELECT (COUNT(?s) as ?numberOfTriples)
>   WHERE {
>     GRAPH <http://digimelding.nl/AStore/stamIndex> {
>       ?s ?p ?o .
>     }
>   }
>
>   Results in:
>   +-------------------------------------------------+
>   | numberOfTriples                                 |
>   +-------------------------------------------------+
>   | "1"^^<http://www.w3.org/2001/XMLSchema#integer> |
>   +-------------------------------------------------+
>
> Query 4: In my quest for the getting the results I wanted I played
> around with various query forms. In my understanding thuis query should
> yield the same results as the previous one. Unfortunately, it doesn't.
>   SELECT (COUNT(?s) as ?numberOfTriples)
>   FROM <http://digimelding.nl/AStore/stamIndex>
>   WHERE {
>       ?s ?p ?o .
>   }
>
>   Results in:
>   +-------------------------------------------------+
>   | numberOfTriples                                 |
>   +-------------------------------------------------+
>   | "0"^^<http://www.w3.org/2001/XMLSchema#integer> |
>   +-------------------------------------------------+
>
> Query 5: Every query targeted on a named graph (UUID) with the actual
> content gives no results. Clearly this query should return ( total
> triples 29 - index triples 1 =) 28 triples. Unfortunately it doesn't.
>   SELECT (COUNT(?s) as ?numberOfTriples)
>   WHERE {
>     GRAPH <7e72ff00-48f1-11e2-bcfd-0800200c9a66> {
>       ?s ?p ?o .
>     }
>   }
>
>   Results in:
>   +-------------------------------------------------+
>   | numberOfTriples                                 |
>   +-------------------------------------------------+
>   | "0"^^<http://www.w3.org/2001/XMLSchema#integer> |
>   +-------------------------------------------------+
>
> My code to execute these queries on Clerezza is actually quite simple:
>
>     Object results = clerezzaManager.executeSparqlQuery( query, new
> SimpleMGraph() );
>
> In here the query is just a string containing one of the queries as
> shown above. Execution uses Clerezza from trunk with my committed
> changes to the QueryEngine.
>
> Does anyone know why query 4 and 5 do not yield the expected outcome?
>
> Regards,
>
> misl
>
> --
> ir. ing. Minto van der Sluis
> Software innovator / renovator
>
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message