What is the correct pattern to update schema with new application release?

If I release first application release, it is ok to generate the schema using schema export. But what if I in the next application release:
- add new fields and tables
- remove some fields or tables and move the contained data elsewhere
- rename some fields

What is the suggested way to solve these changes without data loss? I would like to solve it on the DB backend independent layer so I wouldn't have to care about different SQL dialects. Could someone, please, introduce me to the solutions or direct me to a resource where I could learn it?

Thank you.

I have found interesting thread on this topic here:
http://forum.hibernate.org/viewtopic.php?t=931183