Database security is one of the significant concerns for most DBAs. DBAs frequently restore or backup the database, this is a very common scenario, But the thing is after successfully restoring a new version of your database, you want to remove the current users. Probably you thought of just expanding the user node and deleting the desire user; in that sense you are somewhat correct. But if you face an error like:
Msg 15421, Level 16, State 1, Line 1
The database principal owns a database role and cannot be dropped.
EXEC sp_dropuser '<USER_NAME>' IF EXISTS (SELECT * FROM sys.server_principals WHERE name = N'<USER_NAME>') DROP LOGIN '<USER_NAME>' EXEC sp_droplogin '<USER_NAME>'