RE: DROP COLUMN status

> -----Original Message-----
> From: Bruce Momjian [mailto:pgman@candle.pha.pa.us]
> Sent: Thursday, June 08, 2000 1:58 PM
> 
> [ Charset ISO-8859-1 unsupported, converting... ]
> > > -----Original Message-----
> > > From: pgsql-hackers-owner@hub.org 
> [mailto:pgsql-hackers-owner@hub.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@tpf.co.jp