Re: What is Oracle's objection to the use of Turtle as R2RML syntax?

Souri, what you say here is all correct (well, some nitpicks inline), but I still don't see the key question addressed: What makes one-w3c-RDF-syntax-MUST better in your eyes? All you do below is show that users and implementers will have to go through extra hoops if that proposal is accepted, so you're actually sort of making a case against it…

On 13 Dec 2011, at 16:34, Souripriya Das wrote:
> There are currently two proposed options:
> 1) Turtle-syntax-MUST
> 2) one-w3c-RDF-syntax-MUST
> 
> The Turtle-syntax-MUST option does not support any syntax other than Turtle for the R2RML mapping documents

(Right, R2RML *mapping documents* MUST be Turtle. But implementations MAY still support any syntax other than Turtle.)

> while the one-w3c-RDF-syntax-MUST option only requires at least one of the (W3C Recommendation) RDF syntaxes be used for R2RML mapping documents
> (while, because of the Turtle-convertibility,  still allowing the test cases, tutorials, books, etc. to be written in Turtle).

But one-w3c-RDF-syntax-MUST would equally allow tutorials and books to be written in any other syntax, so we'll get books that teach R2RML using RDF/XML syntax, tutorials that teach R2RML using RDFa syntax, et cetera.

> Again, here is the one-w3c-RDF-syntax-MUST proposal:
> [[
> An R2RML mapping document is any document that encodes an R2RML mapping graph and
> is written in any RDF syntax that is a W3C Recommendation and that can be converted to Turtle.
> ]]
> (By "Turtle" we mean the future Turtle W3C Recommendation)
> 
> The following can be said about the effect of using the above proposal:
> 
> ------------------
> Consider an R2RML mapping document written in RDF/XML syntax:
> - Is it a conforming R2RML mapping document?
> YES. (for Turtle-syntax-MUST: NO)

…and this is literally the *only* difference. I don't understand who benefits from this. Who is keen on calling an R2RML mapping graph serialized in RDF/XML an R2RML mapping document, and why?

> - Why?
> Because one can convert the document to generate an equivalent document written in Turtle syntax.
> 
> ---------------------
> Consider an R2RML mapping processor which ONLY accepts R2RML mapping documents written in RDF/XML syntax:
> - Is it a conforming R2RML mapping processor?
> YES. (for Turtle-syntax-MUST: YES)
> - Why?
> Because it accepts all conforming R2RML mapping documents, written in RDF/XML syntax.
> 
> ---------------------
> Testing for conformance of an R2RML mapping processor that ONLY accepts RDF/XML documents:

Yes, it's possible, but it's inconvenient for implementers. What advantage balances this inconvenience?

> For each test in "tests for conformance"
> 1) obtain the mapping documents (written in Turtle syntax)
> 2) Convert these Turtle-syntax mapping documents into RDF/XML syntax (assuming this is possible)
> 3) Process the converted documents
> 4) Run the corresponding SPARQL queries from "tests for conformance" and compare the results
> 5) If query results match, then this processor is indeed a conforming R2RML mapping processor
> 
> ---------------------
> Sharing of an R2RML mapping document between two non-overlapping syntax accepting processors:

Yes, it's possible, but it's inconvenient for mapping authors and admins. What advantage balances this inconvenience?

I'm not saying that there is no advantage. I'm just saying that I myself can't think of any, and that I can't recall anyone else mentioning any!

So, which stakeholder (WG members, implementers [incl. Oracle], mapping authors) benefits from one-w3c-RDF-syntax-MUST, and how?

Best,
Richard


> - MappingProcessor1 accepts ONLY RDF/XML and MappingProcessor2 accepts ONLY N-Triples
> - an R2RML mapping document (written in RDF/XML) and used at MappingProcessor1 is to be shared with MappingProcessor2
> - convert the mapping document into an equivalent N-Triples document (via Turtle, if direct conversion is not possible)
> - present the N-Triples R2RML mapping document to MappingProcessor2
> 
> Thanks,
> - Souri.
> 
> ----- Original Message -----
> From: richard@cyganiak.de
> To: souripriya.das@oracle.com
> Cc: public-rdb2rdf-wg@w3.org
> Sent: Wednesday, December 7, 2011 1:52:14 PM GMT -05:00 US/Canada Eastern
> Subject: Re: What is Oracle's objection to the use of Turtle as R2RML syntax?
> 
> On 7 Dec 2011, at 18:07, Souripriya Das wrote:
>> Instead of the following definition of the mapping document:
>> 
>> [[
>> An R2RML mapping document is any document written in the Turtle [TURTLE] RDF syntax that encodes an R2RML mapping graph.
>> ]]
>> 
>> we propose the following:
>> 
>> [[
>> An R2RML mapping document is any document that encodes an R2RML mapping graph and
>> is written in any RDF syntax that is a W3C Recommendation and can be converted to Turtle [2].
>> ]]
> 
> Why is this better?
> 
> Richard
>

Received on Tuesday, 13 December 2011 20:09:56 UTC