I'm making a Win app on the 3.5 framework. I'd like to include a database file with the app. This would a single-user db. I looked at the 2 different types of db files I can add, the sdf and mdf. Thw sdf (compact) db is missing some functionality I need, so I prefer the mdf. The description on the mdf file "Service oriented database file" leads me to believe that whoever installed my application would also have to install the SQL service required to access that mdf. Is this correct?
Yes. MDF is just a file and needs a SQL Server database engine to use it.
Yes, at a minimum SQL Express would be required. The advantage of the compact edition is that this requirement is eliminated since the database engine can be x-copy deployed.
来源：https://stackoverflow.com/questions/954419/does-user-need-sql-2008-express-installed-if-i-deploy-app-with-mdf-file