SQL Server 2005 Express SP2

SQL Server 2005 Express Edition is the free (and freely distributable) version of the original SQL Server 2005 program, simpler, more direct and lighter.

Its main function is the development of applications for the management and administration of data, i.e. databases. Every quality database must offer confidentiality and this security is also included in SQL Server Express Edition, guaranteeing data protection and fast processing

Perhaps because of its simplicity, this Express version of SQL is rather designed for small applications, personal use and, to mount your database locally, but if this gets too small you can always upgrade to the full edition and use much more advanced tools.