Re: Is relational theory irrelevant?

But now I sendemail only if the table of addresses is updated. That's most certainly not what I want.
Triggers are tables specific business logic, what we need to model here is an application process.
As a user I want to send email to all my Windows 2000 users to warn them of the newest virus. So I clearly need to exploit predicates. Once the email has been send I want to log that in an audit table so I can prove I (IT security) did my job:

INSERT INTO log SELECT user,

                        sendmail('Beware of virus x', user) as success
                   FROM inventory
                   WHERE os = 'W2K';

Note that log is a generic table. It does not know about emails. Tomorrow it will record other activities, such as which machines were upgraded to Linux ;-)

Cheers
Serge

PS: I trust the readers will distinguish between a (silly) example and generalization. So please don't overvalue the chosen schema

-- 
Serge Rielau
DB2 SQL Compiler Development
IBM Toronto Lab