Re: pg_dump: use ALTER TABLE for PKs

On Wed, 20 Feb 2002, Philip Warner wrote:

> At 13:07 19/02/02 -0800, Stephan Szabo wrote:
> >>
> >> CREATE TABLE PARENT(F1 INT PRIMARY KEY);
> >> CREATE TABLE CHILD(...) INHERIT PARENT
> >>
> >> this should create a PK on CHILD; what does pg-dump and the ALTER TABLE
> >> implementation do? Not sure how it should work, but ultimately we need to
> >
> >Unless it was changed between rc2 and release, the above type of
> >sequence does not end up with a primary key on child(f1).
>
> Interesting, - that makes pg_dumps job easier. Are any constraints ever
> inherited?

Check constraints and not null I believe are inherited by default.
But I just thought of a case that won't dump and restore the same as it
was originally made because we support ONLY on alter table add constraint.

create table z(a int);
create table z2() inherits(z);
alter table only z add constraint foo1 check(a>4);

will make z have a constraint on a but not z2 and the check will get
dumped as part of z's definition which will restore with z2 having
the check.