Re: NULLs: theoretical problems?
Date: Fri, 17 Aug 2007 17:55:41 +0100
"Brian Selzer" <brian_at_selzer-software.com> wrote in message
> "Jan Hidders" <hidders_at_gmail.com> wrote in message
>> Just a minor technicality. As far as I understand it an equality
>> constraint can be represented by two inclusion dependencies in both
>> directions, so I would say that it *is* supported by SQL. Anything I'm
> Yes. SQL doesn't support multiple assignment. In order to get rows with
> new key values inserted, at least one of the constraints needs to be
SQL doesn't properly support relational assignment of either the single or multiple kind. As far as I'm aware however, multiple assignment of a sort could be possible via an updateable view. ie.:
INSERT INTO v (a,b) VALUES (1,1);
is potentially valid even if a and b belong to separate base tables. Or is there some absurd restriction that disallows this?
-- David PortasReceived on Fri Aug 17 2007 - 18:55:41 CEST