You asked for a tool or application answer, but what you really need is a a process answer. The underlying theme here is that you should be versioning your database DDL (and DML, when needed) and providing change scripts to be able to update any version of your database to a higher version.
This set of links provided by Jeff Atwood and written by K. Scott Allen explain in detail what this ought to look like - and they do it better than I can possibly write up here: http://www.codinghorror.com/blog/2008/02/get-your-database-under-version-control.html
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…