Doctrine DBAL & ORM Bundle for the Symfony Framework.
Because Symfony 2 does not want to force or suggest a specific persistence solutions on the users this bundle was removed from the core of the Symfony 2 framework. Doctrine2 will still be a major player in the Symfony world and the bundle is maintained by developers in the Doctrine and Symfony communities.
IMPORTANT: This bundle is developed for Symfony 2.1 and up. For Symfony 2.0 applications the DoctrineBundle is still shipped with the core Symfony repository.
What is Doctrine?
The Doctrine Project is the home of a selected set of PHP libraries primarily focused on providing persistence services and related functionality. Its prize projects are a Object Relational Mapper and the Database Abstraction Layer it is built on top of. You can read more about the projects below or view a list of all projects.
Object relational mapper (ORM) for PHP that sits on top of a powerful database abstraction layer (DBAL). One of its key features is the option to write database queries in a proprietary object oriented SQL dialect called Doctrine Query Language (DQL), inspired by Hibernates HQL. This provides developers with a powerful alternative to SQL that maintains flexibility without requiring unnecessary code duplication.
DBAL is a powerful database abstraction layer with many features for database schema introspection, schema management and PDO abstraction.