RE: DROP COLUMN status

> -----Original Message-----
> From: Bruce Momjian [mailto:pgman(at)candle(dot)pha(dot)pa(dot)us]
> Sent: Thursday, June 08, 2000 1:58 PM
>
> [ Charset ISO-8859-1 unsupported, converting... ]
> > > -----Original Message-----
> > > From: pgsql-hackers-owner(at)hub(dot)org
> [mailto:pgsql-hackers-owner(at)hub(dot)org]On
> > > Behalf Of Bruce Momjian
> > >
> > > Can someone comment on where we are with DROP COLUMN?
> > >
> >
> > I've already committed my trial implementation 3 months ago.
> > They are $ifdef'd by _DROP_COLUMN_HACK__.
> > Please enable the feature and evaluate it.
> > You could enable the feature without initdb.
>
> OK, can you explain how it works, and add any needed documentation so we
> can enable it.
>

First it's only a trial so I don't implement it completely.
Especially I don't completely drop related objects
(FK_constraint,triggers,views etc). I don't know whether
we could drop them properly or not.

The implementation makes the dropped column invisible by
changing its attnum to -attnum - offset(currently 20) and
attnam to ("*already Dropped%d",attnum). It doesn't touch
the table at all. After dropping a column insert/update
operation regards the column as NULL and other related
stuff simply ignores the column.

Regards.

Hiroshi Inoue
Inoue(at)tpf(dot)co(dot)jp