You can use Oracle Enterprise Manager until Oracle9i, or DB console, or Grid Control from Oracle10g and afterwards to get email notifications about everything. But I don’t like it, and especially when a database has thousands of sessions. For example for more than 3000 sessions, the Grid Control takes appoximately a 10% of the machine’s processing power, so i prefer my own alert mechanisms.  For more info you can use this best essay service to having a wonderful assistant in writing and even you can get the guidelines too.