The database is a critical part of your application. If you deploy version 2.0 of your application against version 1.0 of your database, what do you get? A broken application, that's what. That's why your database should always be under source control, right next to your application code. You deploy the app, and you deploy the database. Like peanut butter and chocolate, they are two great tastes that taste great together.
Coding Horror: Get Your Database Under Version Control