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 --
