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

Richard,

On Wed, Dec 14, 2011 at 1:39 PM, Richard Cyganiak <richard@cyganiak.de>wrote:

> Juan,
>
> On 14 Dec 2011, at 13:44, Juan Sequeda wrote:
> > 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.
>
> Are you ok with a phrasing that says that R2RML processors MAY support
> other syntaxes? (Saying SHOULD seems difficult because then you kind of
> want to say which ones should be supported; and that's a tough call.)
>
>
Fine by me.


> > 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.
>
> Well, AFAIK the major ontology editors all can read and write Turtle.
>

Even better.


>
> > Will people actually do this? I don't know.
>
> (D2RQ can read only Turtle. It would be very easy to add support for other
> syntaxes, but demand hasn't materialized. And D2RQ dates back to the days
> when RDF/XML ruled and very few knew about Turtle and N3! In the API
> there's also a backdoor that allows initialization of a D2RQ instance with
> an abstract Jena model, meaning that it's relatively easy for a programmer
> to use a D2RQ mapping from absolutely any RDF source. I know that a number
> of people have used this API backdoor, for example so that they can read
> the D2RQ mapping directly from a triple store.)
>

Good to know.


>
> Best,
> Richard
>
>
>
> > 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
> > > Google+ Profile: https://plus.google.com/112399767740508618350/about
> > > LinkedIn Profile: http://www.linkedin.com/in/kidehen
> > >
> > >
> > >
> > >
> > >
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> > >
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