Maybe this will help:
com.hp.hpl.jena.sparql.core.DynamicDatasets
which is what TDB uses.
Andy
On 30/09/13 14:35, Arthur Vaïsse-Lesteven wrote:
Have you considered using GRAPH in the query? That is the better way to
access a specific graph. GRAPH accesses the dataset's graphs, while FROM
describes the dataset.
Yes I had, but here I have no choice considering my goal. I build a SPARQL
proxy based on the work of Costabello and Gandon ( INRIA sophia antipolis :
http://wimmics.inria.fr/projects/shi3ld/ )
This proxy rewrite on the fly SPARQL queries and and FROM <graph> clauses to
restrict the range of the query. Realising that FROM interpretation can change
depending the endpoint implementation is very annoying. It doesn't appear explicitly
in the standard, but I have to live with it.
I was just in integration trouble as the way Fuseki was start totally impacted
the core functionalities of the security layer.
Arthur VAÏSSE-LESTEVEN
________________________________
De : Andy Seaborne <[email protected]>
À : [email protected]
Envoyé le : Lundi 30 septembre 2013 15h22
Objet : Re: Trubble with config.ttl that impact queries' semantics
On 30/09/13 07:44, Arthur Vaïsse-Lesteven wrote:
Hi again,
What's in config.ttl?
I made my tests with the default file "config.ttl" that defined 2 datasets, "ds" and "books". As
"books" doesn't support SPARQL update I made my tests on "ds".
Testing with the default "config-tdb.ttl" allow the 2 queries to work on the "TDB
Service (RW)" dataset.
Just to check if I correctly understood,
If my query contains "FROM <http://example.com#MyGraph>"
In case of TDB the service will check if any local graph match this URI.
Others will send an HTTP get to http://example.com#MyGraph, and execute the
query on the dataset built on the base of this result.
That is correct ?
Yes.
Can we swap a non-TDB service to a TDB behaviour concerning the "from <graph
uri>" ?
Not in the current codebase. The behaviour of FROM to GET a URL
remotely is a valid usecase. There could be another implementation of
DatasetGraph that provided dynamic datasets. (I have unfinished code in
my personal github to do this.)
If yes, I supposed we have to override some class to change this behaviour.
Have you considered using GRAPH in the query? That is the better way to
access a specific graph. GRAPH accesses the dataset's graphs, while FROM
describes the dataset.
PREFIX uso: <http://weblab.ow2.org/SWAG_users_ontology#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
SELECT ?p ?o ?n
WHERE {
GRAPH <http://swag_data.com/users_graph> {
?user uso:name "[email protected]"^^xsd:String.
?user uso:password "liferay_portal"^^xsd:String.
?user ?p ?o.
OPTIONAL { ?o uso:name ?n }
}
}
Arthur VAÏSSE-LESTEVEN
