Re: Foreign key in Oracle Sql

Mark D Powell wrote:
> With Oracle after you perform an alter table statement all of the
> pre-existing constraints will still be valid and do not have to be
> re-validated. If there would be any type of conflict the alter
> statement would error off to begin with.
>
> It is very unfortunate that there were people on the ANSI committee
> that took the non-procedural language SQL and then specified that it
> should work in a procedural manner. Instead of saying if you start with
> set A and set B and perform a join operation on it with these operators
> (conditions) you should get set C and left how the SQL engine performed
> the work to the engine developers the committee actually went so far as
> to specify how the problem should be solved internally. What a shame.
> IMHO -- Mark D Powell --

On the other side one should acknowledge that not a single major player in the RDBMS marketplace has actually followed the ANSI Committee's recommendations. They take what they want and ignore what they don't.

So in Oracle, for example, one can in fact apply foreign key constraints without validity checking if one wishes to. It isn't the default but it can certainly be done.

-- 
Daniel A. Morgan
University of Washington
damorgan_at_x.washington.edu
(replace 'x' with 'u' to respond)