On 1/5/11 7:38 AM, Lars Marius Garshol wrote:
I want to implement a service which polls a remote URL for updates and applies
any changes found to a local graph. However, I do not want to replace the
entire graph, just those bits which have changed. The remote URL is basically
an Atom feed of changes, which is how I'm able to do this.
We originally thought the sponger would be the way to do this, but as far as I
can see, every time a sponger loads a resource the entire graph is replaced. Is
this correct?
No, it depends on cache invalidation scheme in place. You have to
explicitly force it to override cache.
Specifically, I wanted to write a cartridge in Python that would load the
changes and modify the graph. However, the only example I've found seems to
replace the entire graph:
http://www.ebusiness-unibw.org/wiki/Python4Spongers
Cartridges are part of the overall Sponger Middleware architecture. You
typically SPARQL against a Data Source (URL) via Sponger or use it
indirectly via some of our client tools. Of course, you can use it
directly via URL patterns (RESTfully) and even a Virtuoso/PL API, but in
all cases, cache invalidation scheme plays a role.
Am I better off writing something which uses SPARQL Update (SPARUL?) to make
the modifications?
Depends on if you've exploited all the Sponger options.
Also, which SPARQL Update language does Virtuoso implement? The SPARQL 1.1
Update draft?
http://www.w3.org/TR/sparql11-update/
If so, which version?
SPARQL 1.1.
Kingsley
--Lars M.
http://www.garshol.priv.no/tmphoto/
http://www.garshol.priv.no/blog/
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