SQL Server 2005 Compact edition runs as an in-process application, with a very small footprint (less than 2 MB disk footprint) offering you a good subset of the T-SQL features, and replication features of a full blown SQL install. DB Size is capped at 4GB, should you want to be able to deal with that amount of data on a portable device.
– SQL Server Compact Edition is tightly integrated with Microsoft Visual Studio
– As the database is embedded in the application, little or no management is required.
– It even has self healing and management technologies built in to handle “instant off” and dead battery scenarios in mobile devices.
System requirements: http://www.microsoft.com/sql/editions/compact/sysreqs.mspx
SQL Server 2005 Compact on Microsoft.com: http://www.microsoft.com/sql/editions/compact/default.mspx
Download SQL Server 2005 Compact: http://www.microsoft.com/sql/editions/compact/downloads.mspx