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

On Wed, Dec 14, 2011 at 5:23 AM, Richard Cyganiak <richard@cyganiak.de>wrote:

> Souri,
>
> On 13 Dec 2011, at 23:40, Souripriya Das wrote:
> > OWL too was called a language, "Web Ontology Language". But, it just
> defined a vocabulary. It did not define any syntax.
>
> OWL defines three new syntaxes:
>
> http://www.w3.org/TR/owl2-syntax/
> http://www.w3.org/TR/owl2-xml-serialization/
> http://www.w3.org/TR/owl2-manchester-syntax/
>
> > One can use any RDF syntax (RDF/XML, N-Triple, ...) for OWL.
>
> [[
> As noted above, any conformant OWL 2 tool MUST accept ontology documents
> using the RDF/XML serialization … A conformant OWL 2 tool MAY also accept
> ontology documents using other serializations, for example Turtle
> ]]
> http://www.w3.org/TR/owl2-conformance/#Tool_Conformance
>
> RDF/XML is the single normative OWL syntax. My desire is to have a single
> normative R2RML syntax (but it should be Turtle rather than the outdated
> and in many ways broken RDF/XML).
>

Ok. I'm now convinced. If RDF/XML is the single normative OWL syntax, then
there should be a single normative R2RML syntax too... and RDF/XML is too
complicated for this. So you got my vote for Turtle to be the "single
normative R2RML syntax".

However, other syntaxes *should* be supported by implementations. R2RML is
basically a vocabulary. Written in Turtle, it looks like a language, but
it's still a vocabulary. R2RML mappings are instantiations of this
vocabulary. So technically, I can import the R2RML vocabulary into an
ontology editor, and use the ontology editor to create the mappings. Does
this really work right now? I don't know. Will people actually do this? I
don't know. But it could. And all these tools support different syntaxes.
So if I were to create an R2RML mapping using an existing ontology editor
tool, export it as RDF/XML and send it to somebody else and they open it in
an R2RML specific tool.. everything should work.


> Best,
> Richard
>
>
>
> >
> > Thanks,
> > - Souri.
> >
> > ----- Original Message -----
> > From: kidehen@openlinksw.com
> > To: public-rdb2rdf-wg@w3.org
> > Sent: Tuesday, December 13, 2011 5:01:24 PM GMT -05:00 US/Canada Eastern
> > Subject: Re: What is Oracle's objection to the use of Turtle as R2RML
> syntax?
> >
> > On 12/13/11 4:51 PM, Richard Cyganiak wrote:
> >> Hi Ashok,
> >>
> >> On 13 Dec 2011, at 21:11, ashok malhotra wrote:
> >>> At the Linked Data Workshop last week IBM showed some slides that used
> a RDF syntax called Trig.
> >>> So, I looked up Trig
> http://www.wiwiss.fu-berlin.de/suhl/bizer/TriG/Spec/ and found that you
> were
> >>> one of the authors.  So, Trig might be an alternate syntax for the
> mapping language, no?
> >>> Folks seemed to like it.  It is not a standard but may become one.
> >> I like that example! R2RML already allows the use of TriG syntax, no
> change required. TriG is a superset of Turtle. If you serialize an R2RML
> mapping graph as TriG, you get a Turtle file.
> >>
> >>> It is also possible that
> >>> other RDF syntaxes will appear and one of them will become dominant.
>  If that happens,
> >>> it would be good if users could  write R2RML in the new syntax.
> >> It takes a while for a new syntax to be invented, be implemented, be
> evangelized, become popular, and become a W3C Recommendation. In the case
> of Turtle, 13 years. A future RDB2RDF WG can relax the Turtle requirement
> for a future R2RML version if demand for other syntaxes materializes. This
> is not something that needs to be considered for R2RML 1.0.
> >>
> >> [[
> >> PROPOSAL: On ISSUE-57, let's just go with Turtle in order to get R2RML
> 1.0 out of the door.
> >
> > +1
> >
> > Kingsley
> >> ]]
> >>
> >> Best,
> >> Richard
> >>
> >>
> >>
> >>> All the best, Ashok
> >>>
> >>> On 12/13/2011 12:07 PM, Richard Cyganiak wrote:
> >>>> 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
> >>>>>
> >>
> >>
> >
> >
> > --
> >
> > Regards,
> >
> > Kingsley Idehen
> > Founder&  CEO
> > OpenLink Software
> > Company Web: http://www.openlinksw.com
> > Personal Weblog: http://www.openlinksw.com/blog/~kidehen
> > Twitter/Identi.ca handle: @kidehen
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> >
> >
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