Sqitch is a database change management application. What makes it different from your typical migration-style approaches? A few things:

No opinions
Sqitch is not integrated with any framework, ORM, or platform. Rather, it is a standalone change management system with no opinions about your database engine, application framework, or development environment.

Native scripting
Changes are implemented as scripts native to your selected database engine. Writing a PostgreSQL application? Write SQL scripts for psql. Writing a MySQL-backed app? Write SQL scripts for mysql.

Dependency resolution
Database changes may declare dependencies on other changes—even on changes from other Sqitch projects. This ensures proper order of execution, even when you’ve committed changes to your VCS out-of-order.

No numbering
Change deployment is managed by maintaining a plan file. As such, there is no need to number your changes, although you can if you want. Sqitch doesn’t much care how you name your changes.

Iterative development
Up until you tag and release your application, you can modify your change deployment scripts as often as you like. They’re not locked in just because they’ve been committed to your VCS. This allows you to take an iterative approach to developing your database schema. Or, better, you can do test-driven database development.