Re: R2RML mappings of Non-unique Tables

On Mon, May 14, 2012 at 9:39 AM, Ted Thibodeau Jr <tthibodeau@openlinksw.com
> wrote:

>
> On May 14, 2012, at 10:00 AM, David McNeil wrote:
>
> > On Sun, May 13, 2012 at 12:20 PM, Eric Prud'hommeaux <eric@w3.org>
> wrote:
> >> but that requires computing a query knowing the max cardinality.
> >>
> >> Any idea where to go from here?
> >
> > This query seems to work on PostgreSQL:
> >
> > SELECT generate_series(1, count(*)), fname, lname, amount
> > FROM IOUs
> > GROUP BY fname, lname, amount;
>
> Sure, but note that the generate_series() function is special
> (unique?) to PostgreSQL.
>
> Most other engines require significant yak shaving for similar
> effect, and it may not be achievable with *every* other engine.
>

Indeed. I think a key point of this discussion is that there is not a
generic, standard SQL way of solving the problem. Rather, it will be
realized as vendor-specific SQL.

-David