Re: Semweb ontology-to-ontology

Hello Paul

You're mentioning tools like Pentaho Data Integration and Informatica
Workbench for non-ETL tools? You could use Pentaho for integrating RDF
stores; for instance, you can add the jdbc driver for Virtuoso to the
Pentaho installation and connect to it using "Table Input", as you would in
a relational database, and put a SPARQL query in it. I never worked with
SPARUL to update information, but I guess it will be the same thing.

If you want query rewriting integration (i.e., you don't replicate data,
but issue queries on a global data base as if you did, and the query is
rewritten to integrate different sources and transform your data), then you
should  check the SERVICE clause in SPARQL 1.1, which allows you to join
RDFs from several sources. You should check FedX as well, as it claims to
have better optimizations, suited for federations.

And since we're in this subject, my SPARQLFederator project does that
automatically and with inference:

https://github.com/djogopatrao/SPARQLFederator/

So you specify in an ontology which are the endpoints you wish to
integrate, which classes each endpoint specifies, and the inference axioms.
SPARQLFederator will translate then a conjunctive query into SPARQL,
expanding inference axioms and adding SERVICE clauses to federate data.

Cheers,

--
diogo patrão



On Thu, Oct 9, 2014 at 6:28 PM, Paul Trevithick <ptrevithick@gmail.com>
wrote:

> I'm working on project that involves integrating data from many disparate
> sources into an RDF repository-based data warehouse. We plan to develop an
> OWL ontology for data in the repository. We plan to code up data connectors
> to perform ETL operations and populate the repository with RDF data that
> adheres to this common ontology. The data sources use various access
> methods, data formats and schemas.
>
> In the non-semweb world there are technologies that allow the "source" and
> the "target" schemas to be defined, that allow declarative rules to be
> developed (sometimes by point and click tools) the source schema to the
> target schemas, and code that consumes these rules and transforms the data
> into the target schema. In the non-webweb world our data connectors could
> leverage these technologies.
>
> Are there emerging best practices for doing the equivalent of schema
> mapping in semweb world? We'd like to limit our data connector code to
> generating RDF triples from a data source, and rely on some other
> technology to, given some kind of ontology-to-ontology mapping rules,
> transform RDF data adhering to the source ontology into RDF data adhering
> to the repository's target ontology.
>
> Paul
>