Description
int 
mysql_change_user ( string user, string password [, string database [, resource link_identifier]] )
   mysql_change_user() changes the logged in user
   of the current active connection, or the connection given by the
   optional link_identifier parameter. If a
   database is specified, this will be the current database after
   the user has been changed. If the new user and password
   authorization fails, the current connected user stays active.
  
   This function is deprecated and no longer exists in PHP.