How to restrict number of connections to a database

Today, one of my friend at workstation asked me "How to restrict the number of users connected to a DB in a SQL server"?

Initially, my answer was as easy as to configure the user connection option to the required number using sp_configure.

sp_configure 'user connections',100
RECONFIGURE

There is a break!!!It can only be done at server level. What about at DB level???

From SQL Server 2005 sp2, there a feature called LOGON Trigger. How about using the feature???Yes, it is very well possible
using Logon trigger by rolling back the connections once it reached a maximum required connections.It is not at DB level, but through Login.

create trigger AuditLogin
on database_Name
with execute as self
for logon
as
begin
 IF ORIGINAL_LOGIN()= '< Login Name > ' AND
  (SELECT COUNT(*) FROM sys.dm_exec_sessions
   WHERE is_user_process = 1 AND
   original_login_name = '< Login Name > ) > 10
 ROLLBACK;
end