Microsoft SQL Server 2008 R2 Developer allows developers to build and test any type of application with SQL Server. This edition features all of the functionality of SQL Server Enterprise but is licensed only for development, test and demo use. Applications and databases developed on this edition can easily be upgraded to SQL Server 2008 Enterprise.

What's new in R2?
Built on SQL Server 2008, SQL Server 2008 R2 delivers higher mission-critical scale, more efficient IT, and expanded reporting and analytics through self-service business intelligence. SQL Server 2008 R2 introduces two new premium editions to meet the needs of large scale datacenters and data warehouses.