login and high score

Hi... I would like to create an online game in SL 3. but it's just one player, so the player should login into it, and it's mean they have a carracter to play it with their own account(Name). this is my first project, I use C# on it. Can you give me an example. In this game, there's a score where the top score from many player who's play it is the winner. So, is it need a database.? what database I should use.? Teach me more please. I'm only have any example about SL 3 Game where I found, but there's nothing login or like what I make.

there's a high score.. so it is need connect to database.? is there any example about it.?