Re: relationship in the database

>> TTM is a book to read carefully. Just two pages on from that
>> quote they explain how UPDATE is supported.

>Yes - but not in the sense of an SQL update. The key is not
>changed.

Rubdish. Their UPDATE macro works with CK updates. I use that fact in my example in the other post to support referential actions, which BTW could be easily automated, the RDBMS just needs add:

 ,T2 :=      ( T2 JOIN old ON A = old_A ) {old.A as A, T2.B}
 ,T3 :=      ( T3 JOIN old ON A = old_A ) {old.A as A, T3.B}
 ,T4 :=      ( T4 JOIN old ON A = old_A ) {old.A as A, T4.B}

for each FK between T1 and Tn, whenever a user blindly requests a UPDATE of T1.

Also, I'm not going to argue about Syntax (except to say that I agree that the comma syntax for multiple assignment is ugly, and also the SQL UPDATE syntax is nasty as you can't nest them), nor will I touch ACID (well not today).

Regards
Paul Vernon
Business Intelligence, IBM Global Services Received on Fri Sep 27 2002 - 13:14:11 CEST