[JENA-1419] Documentation issue on the SPARQL datasets

• Type: Documentation
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: Jena 3.5.0
• Fix Version/s: Jena 3.9.0
• Component/s: ARQ, Documentation

Environment

ArchLinux

• Assignee: Andy Seaborne
• Reporter: Jonathan Bisson
• Created: 07/Nov/17 00:07
• Updated: 08/Oct/18 20:29
• Resolved: 07/Sep/18 10:50

Description

In section:
http://jena.apache.org/tutorials/sparql_datasets.html#querying-a-specific-graph

The output is empty. As if the graph couldn't be found.

PREFIX : <[file:///home/jo/eclipse-workspace/sparql_tutorial_data/]>
 PREFIX dc: <[http://purl.org/dc/elements/1.1/]>

SELECT *
 WHERE
 { GRAPH ?g

{ ?b dc:title ?title }

}

Gives:

--------------------------------------------------------------------
|b|title|g|

====================================================================
|_:b0|"Harry Potter and the Chamber of Secrets"|<ds-ng-1.ttl>|
|_:b1|"Harry Potter and the Philospher's Stone"|<ds-ng-1.ttl>|
|_:b2|"Harry Potter and the Sorcerer's Stone"|<ds-ng-2.ttl>|
|_:b3|"Harry Potter and the Chamber of Secrets"|<ds-ng-2.ttl>|

--------------------------------------------------------------------

PREFIX dc: <[http://purl.org/dc/elements/1.1/]>
 PREFIX : <.>

SELECT ?title
 {
 GRAPH :ds-ng-2.ttl

{ ?b dc:title ?title }

}

Gives

---------
|title|

=========
 ---------

Running with Jena 3.5.0, on Linux (Arch)

 $ arq --graph ds-dft.ttl --namedgraph ds-ng-1.ttl --namedgraph \
 ds-ng-2.ttl --query q-ds-3.rq

There is also a problem with q-ds-4.rq:

 ----------------
|date|title|

================
 ----------------

And same with q-ds-5.rq.

---------------------------------------------------------------------------------------
|s|p|o|g|

=======================================================================================
|:ds-ng-1.ttl|dc:date|"2005-07-14T03:18:56+01:00"^^xsd:dateTime| |
|:ds-ng-2.ttl|dc:date|"2005-09-22T05:53:05+01:00"^^xsd:dateTime| |
|_:b0|dc:title|"Harry Potter and the Chamber of Secrets"|<ds-ng-1.ttl>|
|_:b1|dc:title|"Harry Potter and the Philospher's Stone"|<ds-ng-1.ttl>|
|_:b2|dc:title|"Harry Potter and the Sorcerer's Stone"|<ds-ng-2.ttl>|
|_:b3|dc:title|"Harry Potter and the Chamber of Secrets"|<ds-ng-2.ttl>|

---------------------------------------------------------------------------------------

We see that g and s are not in the same format.

Looking around, I found that:
https://github.com/apache/jena/blob/master/jena-arq/etc/dataset.ttl

And made a dataset such as:

 @prefix dc: <[http://purl.org/dc/elements/1.1/]> .
 @prefix rdfs: <[http://www.w3.org/2000/01/rdf-schema#|http://www.w3.org/2000/01/rdf-schema]> .
 @prefix rdf: <[http://www.w3.org/1999/02/22-rdf-syntax-ns#|http://www.w3.org/1999/02/22-rdf-syntax-ns]> .
 @prefix xsd: <[http://www.w3.org/2001/XMLSchema#|http://www.w3.org/2001/XMLSchema]> .
 @prefix ja: <[http://jena.hpl.hp.com/2005/11/Assembler#|http://jena.hpl.hp.com/2005/11/Assembler]> .
 @prefix : <#> .

<> rdf:type ja:RDFDataset ;
 ja:defaultGraph
 [ rdf:type ja:MemoryModel] ;
 ja:namedGraph [ ja:graphName <[http://example/graph1]> ;
 ja:graph :data1 ] ;
 ja:namedGraph [ ja:graphName <[http://example/graph2]> ;
 ja:graph :data2 ] ;
 .
 :data1 rdf:type ja:MemoryModel ;
 ja:content [ja:externalContent <ds-ng-1.ttl> ;
 dc:date "2005-07-14T03:18:56+01:00"^^xsd:dateTime] ;
 .

:data2 rdf:type ja:MemoryModel ;
 ja:content [ja:externalContent <ds-ng-2.ttl> ;
 dc:date "2005-09-22T05:53:05+01:00"^^xsd:dateTime] ;
 .

Using that I was able to query them, but still not by date. There
doesn't seem to be a default graph anymore.