That stratergy of opening the connection at the beginning of the program and closing it at the end is fine for smaller programs not intended for multiple users. However, when you get to developing more complex programs that may have many users connecting to remote databases, that stratergy is not good.

One of the fundemental considerations when coding n-tier applications is to Open connections late and close them early, the opposite of the above stratergy. Doing this will help minimize resource use.

Yes, I know there are things like connection pooling to help with those matters, but it is something to consider.