Mark James wrote:
Hi,
Is it possible to cache data (in the quad store) retrieved by a sparql
query against an rdf view much like a sponger query?
Eg. (Using northwind demo db)
select *
from <http://localhost:8890/Demo#>
where { ?s <http://localhost:8890/schemas/Demo/shipname> 'Rancho grande' }
returns 5 rows. However if I then run -
You asked for a solution (resultset) setting your data source scope to a
Named Graph IRI (partition hosting the records). This Named Graph was
created as part of the RDF View Generation process.
select *
where { ?s <http://localhost:8890/schemas/Demo/shipname> 'Rancho grande' }
no rows are returned as expected.
This query is scoped to the Default Graph which doesn't have any matches
for the query.
If however I browse on of the original returned rows directly eg
http://localhost:8890/about/html/http://localhost:8890/Demo/orders/OrderID/10448#this
The RDF View generation process has a Re-write rule scoped to the Named
Graph IRI hosting the records (triples) in question.
And then run
select *
where { ?s <http://localhost:8890/schemas/Demo/shipname> 'Rancho grande' }
A row has been returned as it is now cached in the quad store.
When you de-referenced the above via the Sponger you used the Linked
Data published via the RDF View to create a Triple in the Quad Store
which is scoped to the Default Named Graph, which is why you get data.
You have a Virtual Triples hosting Named Graph (produced by the RDF
Views creation process) and a conventional Quad Store Default Graph re.
effect of Sponging the Published RDF View Entity URIs.
I would like to get the same cache functionality via my original query.
What you need is the ability, at RDF View creation time, to generate
Triples in the Default Graph (in a sense make Persistent Triples from
the Virtual ones in the RDF Views Named Graph). This is coming, in the
meantime, there is a script for doing this, I'll have some one post it here.
My reasoning is that there is an opportunity to hit some operational
databases overnight and generate reports using rdf views. However as
these databases will be unavailable for querying during the day all
investigations on the data used for the reports would need to rely on
cached data.
Is there a way to do this? It would also be nice to have mechanisms to
only get data if it didn't already exist or was of a certain age much
like the sponger does.
Yes, as per my comments above. This also gives you the additional
benefits of using the Faceted Browers and Inference Rules etc :-)
Kingsley
Cheers
Mark
------------------------------------------------------------------------
------------------------------------------------------------------------------
Download Intel® Parallel Studio Eval
Try the new software tools for yourself. Speed compiling, find bugs
proactively, and fine-tune applications for parallel performance.
See why Intel Parallel Studio got high marks during beta.
http://p.sf.net/sfu/intel-sw-dev
------------------------------------------------------------------------
_______________________________________________
Virtuoso-users mailing list
Virtuoso-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/virtuoso-users
--
Regards,
Kingsley Idehen
President & CEO
OpenLink Software
Web: http://www.openlinksw.com
Weblog: http://www.openlinksw.com/blog/~kidehen
Twitter/Identi.ca: kidehen
