Re: Is relational theory irrelevant?

"Serge Rielau" <srielau_at_ca.eye-bee-m.com> wrote in message news:bpdge7$pv$1_at_hanover.torolab.ibm.com...
> Joe "Nuke Me Xemu" Foster wrote:
>
> > "Serge Rielau" <srielau_at_ca.eye-bee-m.com> wrote in message
<news:bpc4ci$ogk$1_at_hanover.torolab.ibm.com>...
> >
> >
> >>Ragarding c) the realtional model is built for semantic beauty. Semantic
> >>beauty does not make for a fast web-experience. Pipelining however does.
> >>So a lot of effort is being made to pipeline SQL. Often the rules of the
> >>relational model are bent to get there.
> >
> >
> > This is because SQL is so b0rked. Query optimizers' hands are
> > tied because most any transformation could change the results.
> >
> >
> >>Example:
> >>SELECT * FROM (SELECT sendmail() FROM T) AS X WHERE c1 > 100;
> >>How many emails shall be send? Correct (IMHO) would be: As many emails
> >>as there are rows in T. In reality many DBMS will push the predicate
> >>through to T for the sake of speed, and most customers evidently don't
care.
> >
> >
> > Agreed, queries calling functions with side effects is b0rked.
> >
> >
> Interesting. I didn't intend to allege that side-effects are bad. They
> are a reminder that SQL has to deal with the real world.

Side-effects are bad. I suggest your example was also bad. Sending emails is not data management. Recording the emails sent is data management. A database management system has a role and a function. Sending emails is not its function. A dbms can serve the needs of email transmission without transmitting emails. Received on Tue Nov 18 2003 - 22:35:01 CET