GoogleCodeExporter
commented
9 years ago Further investigation reveals problems in the query used above, but the
following have been observed:
This query seems to work OK:
{{{
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX pf: <http://jena.hpl.hp.com/ARQ/property#>
PREFIX fn: <http://www.w3.org/2005/xpath-functions#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX crm: <http://purl.org/NET/crm-owl#>
PREFIX claros: <http://purl.org/NET/Claros/vocab#>
SELECT ?s (GROUP_CONCAT(?p) as ?id) WHERE
{ ?s rdf:type crm:E22.Man-Made_Object .
?s claros:subject-findLocationName ?p
} GROUP BY ?s ORDER BY ?p LIMIT 20
}}}
But this fails:
{{{
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX pf: <http://jena.hpl.hp.com/ARQ/property#>
PREFIX fn: <http://www.w3.org/2005/xpath-functions#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX crm: <http://purl.org/NET/crm-owl#>
PREFIX claros: <http://purl.org/NET/Claros/vocab#>
SELECT ?s (GROUP_CONCAT(?p) as ?id) WHERE
{ ?s rdf:type crm:E22.Man-Made_Object .
OPTIONAL { ?s claros:subject-findLocationName ?p }
} GROUP BY ?s ORDER BY ?p LIMIT 20
}}}
Thus:
{{{
15:53:31 ERROR - zoo.sparqlite.Processor :: [157] caught unexpected
exception: caught exception during query execution: null
java.lang.NullPointerException
at com.hp.hpl.jena.sparql.expr.aggregate.AggGroupConcat$AccGroupConcat.getValue(AggGroupConcat.java:121)
at com.hp.hpl.jena.sparql.expr.aggregate.AggregatorBase.getValue(AggregatorBase.java:59)
at com.hp.hpl.jena.sparql.engine.iterator.QueryIterGroup.calc(QueryIterGroup.java:118)
at com.hp.hpl.jena.sparql.engine.iterator.QueryIterGroup.<init>(QueryIterGroup.java:32)
at com.hp.hpl.jena.sparql.engine.main.OpExecutor.execute(OpExecutor.java:387)
}}}
---------------------------------------------------
BNODE seems to not behave as expected:
{{{
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX pf: <http://jena.hpl.hp.com/ARQ/property#>
PREFIX fn: <http://www.w3.org/2005/xpath-functions#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX crm: <http://purl.org/NET/crm-owl#>
PREFIX claros: <http://purl.org/NET/Claros/vocab#>
SELECT ?s (BNODE(GROUP_CONCAT(?p)) as ?id) (GROUP_CONCAT(?p) as ?pp) WHERE
{ ?s rdf:type crm:E22.Man-Made_Object .
?s claros:subject-findLocationName ?p
} GROUP BY ?s ORDER BY ?p LIMIT 20
}}}
returns:
{{{
{
"head": {
"vars": [ "s" , "id" , "pp" ]
} ,
"results": {
"bindings": [
{
"s": { "type": "uri" , "value": "http://www.beazley.ox.ac.uk/record/20C48A3D-5631-45F3-AD69-A1E2666A1853" } ,
"id": { "type": "bnode" , "value": "b0" } ,
"pp": { "type": "literal" , "value": " ACHAIA AIGEIRA" }
} ,
{
"s": { "type": "uri" , "value": "http://www.beazley.ox.ac.uk/record/692D41B8-5ED4-4F62-BE53-B7EE04494663" } ,
"id": { "type": "bnode" , "value": "b1" } ,
"pp": { "type": "literal" , "value": " ACHAIA AIGEIRA" }
} ,
{
"s": { "type": "uri" , "value": "http://www.beazley.ox.ac.uk/record/9364BEC2-6857-4815-BA0B-9A1A0CA4DE03" } ,
"id": { "type": "bnode" , "value": "b2" } ,
"pp": { "type": "literal" , "value": " ACHAIA AIGEIRA" }
} ,
{
"s": { "type": "uri" , "value": "http://www.beazley.ox.ac.uk/record/A9FCA4D8-4DEB-4285-8860-3F1711E63424" } ,
"id": { "type": "bnode" , "value": "b3" } ,
"pp": { "type": "literal" , "value": " ACHAIA AIGEIRA" }
} ,
{
"s": { "type": "uri" , "value": "http://www.beazley.ox.ac.uk/record/CFDA14B6-3A47-4139-ADF4-3BF91F7912FA" } ,
"id": { "type": "bnode" , "value": "b4" } ,
"pp": { "type": "literal" , "value": " ACHAIA AIGEIRA" }
} ,
{
"s": { "type": "uri" , "value": "http://www.beazley.ox.ac.uk/record/D1F50B0C-15CA-4C41-9F11-23DADA31C5A4" } ,
"id": { "type": "bnode" , "value": "b5" } ,
"pp": { "type": "literal" , "value": " ACHAIA AIGEIRA" }
} ,
{
"s": { "type": "uri" , "value": "http://www.beazley.ox.ac.uk/record/07234518-3003-4562-A6BD-D4018EA09D40" } ,
"id": { "type": "bnode" , "value": "b6" } ,
"pp": { "type": "literal" , "value": " ACROPOLIS NORTH SLOPE" }
} ,
{
"s": { "type": "uri" , "value": "http://www.beazley.ox.ac.uk/record/13214C95-A48C-4F52-A9D5-44793CB580DC" } ,
"id": { "type": "bnode" , "value": "b7" } ,
"pp": { "type": "literal" , "value": " ACROPOLIS NORTH SLOPE" }
} ,
{
"s": { "type": "uri" , "value": "http://www.beazley.ox.ac.uk/record/1879DB2D-2AFB-4F44-AABE-5B5DF9E7E6E5" } ,
"id": { "type": "bnode" , "value": "b8" } ,
"pp": { "type": "literal" , "value": " ACROPOLIS NORTH SLOPE" }
(etc.)
}}}
---------------------------------------------------
Original comment by gk-goo...@ninebynine.org on 29 Sep 2010 at 3:00
- Added labels: ****
- Removed labels: ****
Original issue reported on code.google.com by
gk-goo...@ninebynine.orgon 29 Sep 2010 at 2:32