Sql Server - Reference Membership Database In Another Database?

I am making a simple ASP.NET webpage for my school organization using VS2010. When I choose "New Website," I see that Visual Studio already sets up a database for managing memberships. I also have my own database (MyDatabase) that I need to use for the site, which contains information about the members of the organization (for example, email, phone-number, etc.)

I need to have a way to find out who the current logged-in user is, and allow them to edit ONLY their information (email, phone-number).The way I have considered doing it is:

- Add a field in MyDatabase called "UserName" and use it as a sort-of foreign key from the other database.

- Get the username of the logged-in user

- Use this username for my queries For example:

// (PseudoCode)
String loggedInUser = MembersDatbase.GetLoggedInUser();
var MemberInfo = SELECT * FROM MyDatabase.Users WHERE UserName=loggedInUser;

-Then the logged-in user will only have access to their information.

I'm not sure about the code yet, but I could probably figure that part out. I'm more interested in hearing if there is a better way of doing this. I do NOT want to merge the two databases into a single database.