Hi Reto,
yes, that was a deliberated decision on early phases. I'd need to look
it up, I do not remember the concrete issue.
Just going a bit deeper into the topic, in querying we are talking not
only about providing native support to query Graph instance, but also to
provide common interfaces to interact with the results.
The idea was to keep the focus on RDF 1.1 concepts before moving to
query. Personally I'd prefer to keep that scope for the first incubator
release, and then start to open discussions about such kind of threads.
But of course we can vote to change that approach.
Cheers,
On 17/03/15 11:05, Reto Gmür wrote:
Hi Sergio,
I'm not sure which deliberate decision you are referring to, is it Issue
#35 in Github?
Anyway, the impl.sparql code is not about extending the API to allow
running queries on a graph, in fact the API isn't extended at all. It's an
implementation of the API which is backed by a SPARQL endpoint. Very often
the triple store doesn't run in the same VM as the client and so it is
necessary that implementation of the API speak to a remote triple store.
This can use some proprietary protocols or standard SPARQL, this is an
implementation for SPARQL and can thus be used against any SPARQL endpoint.
Cheers,
Reto
On Tue, Mar 17, 2015 at 7:41 AM, Sergio Fernández <[email protected]> wrote:
Hi Reto,
thanks for updating us with the status from Clerezza.
In the current Commons RDF API we delivery skipped querying for the early
versions.
Although I'd prefer to keep this approach in the initial steps at ASF (I
hope we can import the code soon...), that's for sure one of the next
points to discuss in the project, where all that experience is valuable.
Cheers,
On 16/03/15 13:02, Reto Gmür wrote:
Hello,
With the new repository the clerezza rdf commons previously in the commons
sandbox are now at:
https://git-wip-us.apache.org/repos/asf/clerezza-rdf-core.git
I will compare that code with the current status of the code in the
incubating rdf-commons project in a later mail.
Now I would like to point to your attention a big step forward towards
CLEREZZA-856. The impl.sparql modules provide an implementation of the API
on top of a SPARQL endpoint. Currently it only supports read access. For
usage example see the tests in
/src/test/java/org/apache/commons/rdf/impl/sparql (
https://git-wip-us.apache.org/repos/asf?p=clerezza-rdf-core.
git;a=tree;f=impl.sparql/src/test/java/org/apache/commons/
rdf/impl/sparql;h=cb9c98bcf427452392e74cd162c08ab308359c13;hb=HEAD
)
The hard part was supporting BlankNodes. The current implementation
handles
them correctly even in tricky situations, however the current code is not
optimized for performance yet. As soon as BlankNodes are involved many
queries have to be sent to the backend. I'm sure some SPARQL wizard could
help making things more efficient.
Since SPARQL is the only standardized methods to query RDF data, I think
being able to façade an RDF Graph accessible via SPARQL is an important
usecase for an RDF API, so it would be good to also have an SPARQL backed
implementation of the API proposal in the incubating commons-rdf
repository.
Cheers,
Reto
--
Sergio Fernández
Partner Technology Manager
Redlink GmbH
m: +43 660 2747 925
e: [email protected]
w: http://redlink.co
--
Sergio Fernández
Partner Technology Manager
Redlink GmbH
m: +43 660 2747 925
e: [email protected]
w: http://redlink.co
