Re: add column .. default

On Thu, 2003-06-19 at 10:42, Tom Lane wrote:
> Rod Taylor <rbt(at)rbt(dot)ca> writes:
> > On Thu, 2003-06-19 at 10:05, Alvaro Herrera wrote:
> >> Sorry, I haven't read the spec, but what happens when there is a default
> >> value already and it's not NULL? Are tuples where column =3D default
> >> updated? Are tuples where column IS NULL updated?
>
> > We're talking about add column. Since it's a new column, there will
> > never be a default and all entries are NULL in PostgreSQL.
>
> That's an overly simplistic analysis, given that the column may already
> exist in child tables. I am not sure that the behavior is fully
> consistent even now in such cases, but we at least should make certain
> it doesn't become less consistent.

Right now if the column exists in the child table, the add column is
rejected. I assume that will remain.

It is consistent with the user providing a column that inherits a column
from a parent by the same name.

--
Rod Taylor <rbt(at)rbt(dot)ca>

PGP Key: http://www.rbt.ca/rbtpub.asc