Re: [PATCHES] Inherited Constraints

On Wed, 8 Mar 2006, Hannu Krosing wrote:

> Ühel kenal päeval, E, 2006-03-06 kell 17:25, kirjutas Bruce Momjian:
> > Hannu Krosing wrote:
> > > ?hel kenal p?eval, E, 2006-03-06 kell 12:12, kirjutas Bruce Momjian:
> > > > Added to TODO:
> > > >
> > > >       o Prevent parent tables from altering or dropping constraints
> > > >         like CHECK that are inherited by child tables
> > > >
> > > >         Dropping constraints should only be possible with CASCADE.
> > > >
> > > > and we already have this in TODO:
> > > >
> > > >         o %Prevent child tables from altering or dropping constraints
> > > >           like CHECK that were inherited from the parent table
> > > >
> > > > so I think we now have all the failure cases documented.
> > >
> > > If you want to be consistent, then ALTER TABLE ONLY ADD CONSTRAINT  ..
> > > should also be forbidden, so you can't create non-inherited constraints
> >
> > I don't have a problem with creating ONLY constraints on parents and
> > children.  We just don't want them to be removed/modified if they are
> > shared.
>
> Well, when you delete a constraint from child, the constraint becomes an
> "ONLY" constraint on parent.

Only if there's a single child, otherwise you have a partially-ONLY
constraint unless you made it ONLY constraints on the parent and all other
children (but then removing the parent constraint wouldn't remove it from
the other children presumably).

> If you allow ONLY constraints on parents, then why disallow dropping
> them from childs ?

I agree with this in any case.  I think both are fairly broken.