Re: Surrogate Keys: an Implementation Issue
Date: Fri, 21 Jul 2006 09:31:12 +0100
"Dan" <guntermann_at_verizon.net> wrote in message
> Roy Hann wrote:
>> "Damien" <Damien_The_Unbeliever_at_hotmail.com> wrote in message
>> > Just a quick question. What if, for whatever reason, you did NOT want
>> > "ON UPDATE CASCADE" semantics? It seems you cannot avoid them in your
>> > situation...
>> Before exerting myself to think of an answer to this, why, after assering
>> that an attribute is a foreign key, would it ever be reasonable not to
>> ON UPDATE CASCADE? If the attribute is not a foreign key, don't say it
> Why wouldn't it be a foreign key with ON UPDATE RESTRICT semantics?
> If I had a wife who was a person with a personal name and personal
> information that was listed in a MARRIED TO relation and further
> constrained to being referenced from a PERSON relation, I wouldn't want
> my new wife to supplant my ex-wife's name, but keep her personal
> information when I changed the name in the MARRIED TO relation and had
> it propagate back to the PERSON table.
Roy Received on Fri Jul 21 2006 - 10:31:12 CEST