Ahead of the final release in December 2006, Microsoft have
released SQL Server Compact Edition RC1.
SQL Server 2005 Compact Edition is a very lightweight, in process relational
database engine for use in desktop applications and mobile devices. It has an
extremely small footprint (~3MB) and minimal overhead. It won’t use any where
near as much memory as Express so its suitable for memory pressured systems. It
works on Windows 2000 SP4, Windows Server 2003 SP1, and Windows XP SP2.