Contained database, new feature in SQL 2012

The main idea of contained database is to remove the independency between the Database Engine and the database. The contained databases are independent databases that do not require a login.

With Contained databases, there is only a small functional dependency on SQL Server Instance or in other words, the database is self-contained and all the objects will reside in the database itself.

Two articles from two diferent sources about the new feature in SQL 2012 "Contained Database".

SQLServerCentral: New features in SQL 2012, the contained database

SQLServerPerformance: Contained Databases in SQL Server 2012