"VistaDB 3 is the world's first fully managed and typesafe SQL database engine designed specifically for the Microsoft .NET Framework, Compact Framework environments, Mono and the upcoming release of Microsoft Windows Vista. This page is provided to inform developers about VistaDB 3 key features, benefits and design goals. Most of the features listed on this page are currently code complete in the recently released Community Technology Preview (CTP). ... To maximize integration into the .NET Framework, Compact Framework, 64-bit .NET Framework and Mono, VistaDB 3 has been completely redesigned and redeveloped using Visual C# to be fully managed and typesafe." 
Recently we had talked about Microsoft
SQL Server 2005 Everywhere Edition, which is the light weight database solution from the Microsoft camp. In case you are exploring alternatives or are unable to find support for certain features in the Microsoft version, then check out VistaDB 3. I haven't done a comparison between the two, but VistaDB 3 seems to offer a lot of features in a small package. The major difference that I noticed is that unlike VistaDB 3, Microsoft's SQL Everywhere is free. We would like to hear your comments if you have evaluated this database engine.
VistaDB 3 - Fully Managed .NET Database Supports Compact Framework
Linear Mode
