- From: Richard Cyganiak <richard@cyganiak.de>
- Date: Tue, 31 May 2011 20:53:10 +0100
- To: Alexandre Bertails <bertails@w3.org>
- Cc: ashok.malhotra@oracle.com, RDB2RDF WG <public-rdb2rdf-wg@w3.org>
Hi Alexandre, On 31 May 2011, at 20:27, Alexandre Bertails wrote: >> I would agree to a proposal that maintains reversibility of the mapping by adding rdfs:domain triples to the properties, and does not generate triples for NULL values. > > I think that for the moment, we can agree on the current proposal > without speaking about any concrete solution, which will come later when > we're ready for it. No, because I'd like to know what I am agreeing to. I would likely be opposed to a solution that introduces a parliament of OWL into the direct mapping in order to work around the NULL issue. > rdfs:domain may be enough for this issue, but we may want other information as well. I think we all agree that rdfs:domain is *necessary*. I believe that it is also *sufficient* to reconstruct the NULLs, and have seen no claims to the contrary. So let's go with rdfs:domain *only* as the resolution to ISSUE-42. More schema triples may still be added to the direct mapping later on, but that needs to be discussed, and it can't be discussed before there's a proposal on the table. So I suggest treating additional schema triples as a different and separate issue (which someone should create in the tracker). PROPOSAL: Resolve ISSUE-42 by not creating triples for NULL values, and adding rdfs:domain statements to the direct mapping graph. This does not preclude adding more schema triples in a future resolution. Best, Richard
Received on Tuesday, 31 May 2011 19:53:39 UTC