Re: Column Drop

On Mon, 26 Apr 1999 12:32:01 GMT, tkyte_at_us.oracle.com (Thomas Kyte) wrote:
>
>
>DROP UNUSED COLUMNS
>removes from the table all columns currently marked as unused. Use
>this command when you want to reclaim the extra disk space from
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>unused columns in the table. If the table contains no unused columns,
>the statement returns with no errors.
>

To reclaim the space, doesn't something similar to the following happen (I'm on 7 so I'm just guessing):

rename TABLE to TMP_TABLE

drop or disable constraints

create table TABLE as (select all undropped columns)

drop TMP_TABLE

enable or rebuild constraints

I like the ANSI compatability (read ease of use), I just like to know what it's really doing.

So, you could mark a column to be dropped during normal business hours and end it's use, but wait to actually rebuild the table until a low usuagecycle, is that right?

-Dean Received on Mon Apr 26 1999 - 19:41:39 CDT