Re: Adding alter column syntax into postgres

Jwexler,

> Please suggest how best to propose that the following feature be added to PostgreSQL's roadmap?
>
> Ability to "Alter column position" as described in the section "Adding alter column syntax into postgres" of
http://wiki.postgresql.org/wiki/Alter_column_position(and the two links in that section).
 

Fortunately, there's already a specification discussed for this.  We'd 
like to have the ability for each column to have both a logical position 
and a physical position which are separate.  This would also allow us to 
dynamically re-arrange the columns at CREATE time for best storage 
efficiency.

It would also provide a foundation for column aliases.

However, I don't think there's much code for this yet.  Are you in a 
position to either write code, or fund work?

> Once implemented in tables, I would suggest a command perhaps similar to that in mysql
(http://trebleclick.blogspot.com/2009/02/reorder-mysql-table-columns.html)as well as adding the feature to pgadmin and
toPostgreSQL views.
 

Hmmmm.  It *might* be worth supporting that for MySQL compatibility, but 
really it hardly seems adequate to a large table where you want to 
rearrange most of the columns.  Seems like we'd need a better syntax.

> I would suggest that addition of this feature should be considered common sense.

Actually, it's not.  Column ordering is supposed to be arbitrary and 
implementation-dependent, so we're on our own here.  However, it would 
help people administer their applications ... even if it encourages bad 
application writers to continue using "SELECT *".

-- 
Josh Berkus
PostgreSQL Experts Inc.
www.pgexperts.com