Re: The Relational Model & Queries That Naturally Return Duplicate Rows

On Oct 11, 5:57 pm, Erwin <e.sm..._at_myonline.be> wrote:
> On 11 okt, 03:51, David BL <davi..._at_iinet.net.au> wrote:

> > The phrase "an ideal RDBMS" doesn't appeal to what's provable. Can
> > "ideal" be defined uniquely and mathematically? I doubt it.
>
> The universal meaning of "ideal" can perhaps not be pinned down, but
> if the OP speaks of "an ideal _R_ DBMS", then I think it is fair to
> infer from that that he speaking about a DBMS that scrutinously and
> faithfully follows all prescriptions of the relational model.

Any DBMS that supports relations could perhaps be called an RDBMS, and an "ideal RDBMS" could mean almost anything depending on who you ask.

I myself have no idea what the OP was really asking. You seem to be assuming the OP was simply asking whether projection should return a set, rather than raising the topic of SQL backward compatibility for a new generation RDBMS that emphasises relations over tables.

For all we know the OP wants to know whether people think their "ideal RDBMS" should support an additional SQL-compatible language - which I think C. Date recommends. Received on Mon Oct 11 2010 - 17:05:09 CEST