Tim Eyres wrote:
>
> Does anybody know the justification for not being able to delete columns
> from tables when using Oracle? Is there a genuine relational database
> principle behind it or is it just an Oracle failing?
>
> Tim
I can imagine a few good reasons:
1. It is not allowed in ANSI-SQL.
2. If you drop a column, you have to invalidate all the checks,
constraints, indexes, triggers, views, procedures and functions that use
that column. That's a lot more work to do than just dropping these
objects when a table is dropped.
3. As another Oraclist mentioned, it would be a very time consuming
procedure that may lock the data dictionary unintentionally for a very
long time. You may just estimate the amount of time doing an update on
that column to null.
--
Martin Haltmayer
Received on Tue Sep 30 1997 - 00:00:00 CDT
