Re: R2RML, v 1.65 2011/06/15: implementation experience.

Hi Ivan,

(I'm cross-posting this to public-rdb2rdf-wg as well, as I'm not sure if everyone in the WG is subscribed to public-rdb2rdf-comments. WG members: If you're not, then you probably should be. Archive, with link to subscription, is here: )

This is great stuff! Many thanks for the detailed report. As an editor of the R2RML document, this is extremely helpful.

On 15 Jun 2011, at 22:05, Ivan Mikhailov wrote:
> Examples are accurate and can be used "as is" for first tests, except
> trivial missing semicolon


> Other minor problem hides in obsolete fig 1b --- fig 9. I'd be lazy to
> patch figures frequently so I'd label them "deprecated" for a while.

I added warnings to all figures.

> The generated text of RDF Views is not perfect, it's rather a draft for
> review and for assigning some meaningful names to individual mapping
> rules, for readability of future error diagnostics etc. I'll probably
> extend source R2RMLs with rdfs:labels, comments etc. in order to make
> the output more readable.

I don't quite understand what you meant to say here. What's “the generated text of RDF Views”? Could you expand a bit?

> Further works: validation
> The open issue for me is the validation of input. The examples use only
> rr:TriplesMap as an explicitly declared type, types of the rest of
> (blank) nodes are defined implicitly as ranges of predicates in use. No
> doubt, that's how people will write their own R2RML resources,
> especially if they will write Turtle. However I'm not sure what's the
> best policy for validation. E.g., one may decide to create a (supposedly
> rr:SubjectMap) node and use it as value of both rr:useSubjectMap and
> rr:useObjectMap predicates in different places, should I warn about
> rr:graph in rr:useObjectMap after that?
> If types are not declared explicitly, should I first infer them and then
> warn about multiple types assigned to same node? Which classes are
> supposed to be disjoint?
> Right now I've sabotaged the coding of the validator, eliminating the
> problem, but that's not a universal solution.

What can the WG do or deliver to help solve this problem?

We have started to collect issues like these on the wiki:

But this obviously still needs a lot of work & thought.


Received on Monday, 20 June 2011 12:01:18 UTC