Re: Q: ISSUE-41 bNode semantics

On 19 May 2011, at 22:30, David McNeil wrote:

> Admittedly this is a long thread and it is hard to follow, but it seems to me that Richard is advocating omitting the NULL values from the Direct Mapping triples and that Enrico is ok with omitting the NULL values from the Direct Mapping, so maybe that is an approach that would have broad support? (This assumes that the Direct Mapping includes the schema information which it sounds like the Direct Mapping editors agree that it should).

Indeed. Basically the schema information allows you to reconstruct the NULL values - as if you had them directly (which is admittedly easier, I guess; and this has been the choice of SQL).
Note that a consequence of this is that the translated data alone is not meaningful anymore as an RDF graph in its solitude, but it should be coupled with schema information *and* a recipe on how to cook all this stuff together: you have to prescribe how queries should be translated in order to give the same/correct answer. 


Received on Thursday, 19 May 2011 20:39:17 UTC