Actually, I was in a hurry. I meant the object does not exist in the database when I desc it in SQL Plus. Thanks a lot for all of your help and responses I am greatful for such a great repsonse. I am very new to Oracle DBA stuff. I would like to ask you guys for another favor. I have searched books on the same matter, such as oracle tuning and dynamic tables and views in oracle. Would you guys recommend a good book which has good reviews for someone like me who wants to delve into V$ views? Thank again.