Maintaining the DB Model

[CJ]

G'day folks,

I'm trying to figure out how to maintain both a current model of our PRODUCTION database, while being able to document proposed changes to that database and being able to generate DDL that can be applied to our TEST database.

I'm thinking that the best thing to do is have a "Produciton" package that is used to reverse-engineer the database.    This package cannot be altered in any way other than refreshing it by reverse engineering the current production database, and maybe adding notes an such.

To add a column to a table:
1) copy the table from the "Production" package to a working package;
2) add a column to copied table;
3) generate DDL for our TEST database;
4) modify the DDL for PRODUCTION;
5) re-import the DDL schema of PRODUCTION into the production package.

Anybody have any alternatives?