<p>Navision is also known as Microsoft Dynamics NAV.</p>

Navision's application logic is written using a proprietary language called C/AL, which is loosely based on Pascal.  It currently offers both a native database option as well as MS SQL Server.
The next version (NAV 2009) will use .NET assemblies served via IIS.  C/AL logic will be translated to C# code and deployed to the server.