jian he <jian(dot)universality(at)gmail(dot)com> writes:
> the attached patch is to implement $subject.
Why would this be a good idea? I don't see any principled fallback
definition of the column. (No, "NULL" is not that.) Certainly we
should support ALTER TABLE DROP COLUMN, but removing the expression
and not providing a substitute seems semantically nonsensical.
regards, tom lane