Consider the following scenario,
An application is compatibile with windows sql server 2003.
Now a service pack has to be added to this baseline version of this application.
After implementing this SP, the application could be run and is compatible with sql server 2008.
A fresh installation of the baseline version of application has to be installed on workstation and then SP implemented on top of it.This makes the application compatible to be run with windows sql server 2008.
Can an existing database (sql server 2003) be upgraded to sql server 2008 on the machine on which it is running at that moment.