Which will run on the mac; this begs the obvious question, why isn't the whole thing being ported? (setting aside asp.net perhaps)
I'll put aside my fanboy rantings of "why would I want to contaminate my Mac with the .NET Framework" because I would LOVE to be able to design Cocoa applications using Interface Builder and write all of my controllers using proper C#, not that Mono stuff.
But there are some technical limitations to porting the entire framework to OS X. Not the least of which is that a lot of the .NET Framework is a wrapper for Win32, which doesn't exist on any Mac platform (either PowerPC or Intel). As far as I know, the specific
database clients use OLEDB to connect to the databases, OS X only has ODBC.