Have you ever heard of separation of concerns? Please read
http://en.wikipedia.org/wiki/Separation_of_concerns[
^].
WPF means "Windows Presentation Foundation", if someone is now aware of it. What should it have to do with databases? If different technological aspect created dependencies and specific preferences, we would not go far in development. The power of engineering, especially in programming, is the ability to freely combine solutions responsible for different aspects of functionality. Please think about it.
As to a selection of database management system, would you make a decision using your own criteria? Here is the comparison chart for you:
http://en.wikipedia.org/wiki/Comparison_of_databases[
^].
—SA