Re: Brain teaser for non-PK tables

Richard, Souri

Do you accept eric's proposal (which hasn't been stated yet):

1) Leave DM as-is
2) Add the following to R2RML

 rr:subjectMap [
    rr:termType rr:RowBlankNode
  ];


Juan Sequeda
+1-575-SEQ-UEDA
www.juansequeda.com


On Thu, May 3, 2012 at 11:08 AM, Michael Hausenblas <
michael.hausenblas@deri.org> wrote:

>
> > Were we close to closing R2RML's CR?
>
> This was the last issue, all other have been resolved in last weeks
> meeting (see also my comments when I sent out the minutes [1]). Never mind,
> we're not extending CR but entering a second, rather short LC period.
>
> Ivan, can you prepare a respective PROPOSAL for next week's meeting please?
>
> Cheers,
>           Michael
>
> [1]
> http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2012May/0005.html
>
> --
> Dr. Michael Hausenblas, Research Fellow
> DERI - Digital Enterprise Research Institute
> NUIG - National University of Ireland, Galway
> Ireland, Europe
> Tel.: +353 91 495730
> WebID: http://sw-app.org/mic.xhtml#i
>
> On 3 May 2012, at 17:04, Eric Prud'hommeaux wrote:
>
> > * Juan Sequeda <juanfederico@gmail.com> [2012-05-03 10:50-0500]
> >> Looks like we have to extend CR till
> >> we have implementations for this corner case.
> >
> > Were we close to closing R2RML's CR?
> >
> >
> >> Juan Sequeda
> >> www.juansequeda.com
> >>
> >> On May 3, 2012, at 10:42 AM, Richard Cyganiak <richard@cyganiak.de>
> wrote:
> >>
> >>> On 3 May 2012, at 16:25, Eric Prud'hommeaux wrote:
> >>>> presumes you can create tables, but yeah, conceptually easier query.
> >>>
> >>> (It looks like most databases have a proprietary method of adding the
> indexes that doesn't require write access to the DB.)
> >>>
> >>>> you can even push the symbol generation down:
> >>>
> >>> Right.
> >>>
> >>>>> The big remaining question is: How to handle this in R2RML?
> >>>>
> >>>> Looking for an analog to:
> >>>> rr:subjectMap [
> >>>>      rr:column "ROWID";
> >>>>      rr:termType rr:BlankNode
> >>>>   ];
> >>>> I'd propose:
> >>>> rr:subjectMap [
> >>>>      rr:termType rr:RowBlankNode
> >>>>   ];
> >>>
> >>> That's an option. Even keeping rr:BlankNode would work — the absence
> of an rr:column/rr:template/rr:constant might signal that a fresh blank
> node must be allocated for each row.
> >>>
> >>>> Does that complicate things beyond how much a cardinality requirement
> necessarily complicates things?
> >>>
> >>> Well, the spec only needs to define the graph generated by the
> mapping, so in terms of specification it would be a simple enough change.
> >>>
> >>> The implications for implementers are quite significant though. It's a
> new feature, the implementation costs are not trivial, no existing
> implementation does this (AFAIK), so there's a certain amount of R&D
> required to show that it's implementable.
> >>>
> >>> Best,
> >>> Richard
> >
> > --
> > -ericP
> >
>
>
>