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
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