> > I'm hoping to implement SET NULL / SET NOT NULL for 7.3
> >
> > I've been searching the SQL99 docs but I still can't figure out the syntax
> > for it.
>
> There isn't really a syntax for it. SQL only allows you to add table
> constraints, not column constraints. A NOT NULL constraint is a shorthand
> notation for a CHECK constraint, so to add a NOT NULL constraint you'd
> have to recognize CHECK constraints of the form CHECK (col IS NOT NULL)
> and handle them specially. To drop NOT NULL constraints, you'd use the
> regular ALTER TABLE blah DROP CONSTRAINT foo; where foo is the name of the
> NOT NULL constraint. The drawback is that NOT NULL constraints currently
> don't have a name stored.
While this would imho really be the intuitive approach, does the
feature of dropping a not null constraint really justify storing a name for
each and every one ? With the added complexity of automatically
generating a name that fits and is guaranteed unique (and prbably
predictable) ?
I guess I would rather invent syntax that does without a name.
On the other hand other db's have such syntax and still generate names
for not null constraints, thus allowing both ways of dropping the constraint,
so ...
Andreas
