On Thu, Oct 6, 2011 at 4:16 PM, Florian Pflug <fgp@phlo.org> wrote:
> Sure, but there are still a lot of cases where the database could deduce
> (quite easily) that a result column cannot be null. Other databases do
> that - for example, I believe to remember that Microsoft SQL Server preserves
> NOT NULL constraints if you do
>
> CREATE TABLE bar AS SELECT * from foo;
>
> So the question makes perfect sense, and the answer is: No, postgres currently
> doesn't support that, i.e. doesn't deduce the nullability of result columns,
> not even in the simplest cases.
hm, good point. not sure how it's useful though. I suppose an
application could leverage that for validation purposes, but that's a
stretch I think.
merlin
