Jennifer
Crystal ORM using ActiveRecord pattern with flexible query DSL
...Jennifer allows you to maintain everything for your models - from DB migrations and field mapping to callbacks and building queries. For detailed information see the docs and API documentation. For command management Jennifer uses Sam. Due to this you can easily create/migrate/drop a database or invoke a generator to bootstrap your models and migrations. Jennifer has a built-in database migration management system. Migrations allow you to organize all database changes.