Re: [odata] W3C direct mapping

Hello Ashok,
Uhmm... well, to my understanding the Direct Mapping
( http://www.w3.org/TR/rdb-direct-mapping/ ) - as opposite to R2RML -
does more than producing a schema
It also produces RDF-encoded "facts" (A-boxes in DL) describing the
acutual tuples into the database. Doing so it produces also URIRefs
which are used as subjects, predicates and objects in those RDF
triples. (pls check section 2.1 Direct Mapping Example; this is the
URIRef associated to "Bob" in table "People":
http://foo.example/DB/People/ID=7 )
So my point is: if they provide a way to map a database entry into an
URIRef and OData does the same, why these URIRefs should have
different syntaxes?
Note: sure it is perfectly legal to have two different URIRefs
pointing at the same database entry, but I think the developer
community would appeciate to have an uniform way to do this rather
than two different specs...
What do you think?  Best Regards, Giovanni
Def. Quota Ashok Malhotra <>:
Hi Giovanni: I agree that the OData TC should look at the specs from the W3C RDB2RDF WG.
But I am a bit surprised by your use of the word "syntax" for the
DM. The Direct Mapping
spec essentially describes an algorithm. You give it a Relational
Database schema and
it produces a RDF schema. If you want to customize the schema you
should use its
companion document R2RML which does have a customization syntax. The
documents
are at:  o http://www.w3.org/TR/r2rml/  o http://www.w3.org/TR/rdb-direct-mapping/
All the best, Ashok  On 8/3/2012 2:27 AM, Giovanni Bartolomeo wrote:
Hello,
W3C has recently proposed two recommendations ("direct mapping" and
"R2RML") to map database entries into URIs (better URIRefs). link:
http://www.w3.org/2001/sw/rdb2rdf/
"In the direct mapping of a database the [URIrefs] directly
reflects the names of database schema elements, and neither
structure nor target vocabulary can be changed. [...] With R2RML on
the other hand, a mapping author can define highly customized views
over the relational data."
Since the sintax in the direct mapping is quite similar, but not
the same, to the one used in ODAta, wouldn't it be good to spend
some effort trying to harmonize the two?
Best Regards, Giovanni

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Invito da parte dell'Ateneo: Il tuo futuro e quello della Ricerca Scientifica hanno bisogno del tuo aiuto. Dona il  5 x mille all'Universita' di Roma Tor Vergata codice fiscale: 80213750583  http://5x1000.uniroma2.it