From Postgresql Community:
SQL Server 2008 R2 Express is a free edition of SQL Server that is ideal for learning, developing and powering desktop, web and small server applications, and for redistribution by ISVs. Supports stored procedures, triggers, functions, and views. Store all kinds of business data with native support for relational data, XML, FILESTREAM and spatial data. Improved performance, usability, visualization, in addition to integration with the Microsoft 2007 Office System in SQL Server Reporting Services. If you need a database GUI, you can try Navicat (SQL Server GUI). Simplify development efforts by leveraging existing T-SQL skills, ADO.NET Entity Framework and LINQ. Closely integrated with Visual Studio and Visual Web Developer.