Bruce Momjian <pgman@candle.pha.pa.us> writes:
> Tom Lane wrote:
>> What I was actually wondering about after reading Tim's report was
>> whether we could support zero-column tables, which would eliminate the
>> need for the special case altogether. I have not looked to see how
>> extensive are the places that assume tuples have > 0 columns ...
> Zero-width tables do sound interesting. Is it somehow non-relational?
Dunno. I wasn't really thinking that zero-width tables are all that
useful by themselves, but it does seem natural that you should be able
to redefine a column by
ALTER TABLE mytab DROP COLUMN foo;
ALTER TABLE mytab ADD COLUMN foo ...;
even if foo is the only column in mytab. Right now we reject that.
regards, tom lane