table structural changes

Once the database table is defined,
1. we cannot change the data type of a field (e.g. from varchar -> date)

   without clearing the stored data.

   is there an good way to restore the data if the new and old types    are comaptible? (eg. from number type to char type).        

2. we cannot change the name of a field (e.g. from name -> dept-name)

   I remembered that one suggestion is to manipulate the system catalog to    achieve the goal. But it seems very dangerous. Any other ways?

thanks/david

-- 
David So			Internet: david.so_at_Software.Mitel.COM
Mitel Corp.
350 Legget Drive, Kanata, Ont.  Phone: (613) 592-2122 x3018
CANADA K2K 1X3         		Fax:   (613) 592-4784