Re: Altering a column type - Most efficient way

On Thu, 2008-07-10 at 10:36 +0200, Mario Weilguni wrote:
> Ow Mun Heng schrieb:
> >
> > I want to change a column type from varchar(4) to varchar()
> >
> >
> Example:
> {OLDLEN} = 4
> {NEWLEN} = 60
>
> update pg_attribute
> set atttypmod={NEWLEN}+4
> where attname='the-name-of-the-column'
> and attrelid=(select oid from pg_class where
> relname='the-name-of-the-table')
> and atttypmod={OLDLEN}+4;
>

This is what I see on the table

NEW attypmod = -1
OLD attypmod = 8

I'm not very confident in doint this change since this is not a
development server. If would help though if someone else has any other
suggestion or something.. Thanks for the information though, it's
enlightening knowledge.