The Oracle logon trigger can be a very powerful tool for recording who or what is accessing your database. However, you may not need to know when every user or every host or even a specific application logs into Oracle. The following trigger shows one possibility for selectively auditing user logons.
I came across a problem today in which a user could not reset her password without getting the “ORA-28221: REPLACE not specified” error. The correct “alter user” syntax to resolve this error is: alter user USERNAME identified by NewPassword replace OldPassword;