ASA Database Administration Guide
  Managing User IDs and Permissions
    Managing individual user IDs and permissions

Changing a password

Changing a user's password 

Using the GRANT statement, you can change your password or that of another user if you have DBA authority. For example, the following command changes the password for user ID M_Haneef to new_password:

GRANT CONNECT TO M_Haneef
IDENTIFIED BY new_password

Changing the DBA password 

The default password for the DBA user ID for all databases is SQL. You should change this password to prevent unauthorized access to your database. The following command changes the password for user ID DBA to new_password:

GRANT CONNECT TO DBA
IDENTIFIED BY new_password