Reverse Engineering

Have anyone of you in this forum worked on situations where you had generate DML/DDL for upgrades. I have seen scripts which just lists the differences. I am looking for scripts that might help in comparison and generation of the actual ddl/dml. Anyhelp is appreciated. The DDL/DML that I am looking for is as a result of running a comparison between two databases. One production database and the other with changes that need to make it to the production database.