Is it possible for Oracle database administrator to make direct changes in data contained in a row, for example, changing an amount of 50 to 500 either by typing into the database cell or by executing an update query? If so, how could it be restricted so that data changes could only input through ERP application?
If you have Enterprise Edition you can purchase the Database Vault option, which can be used to lock the DBA and SYSDBA accounts out of specific schemas. Otherwise there is no way to prevent a DBA or SYSDBA user (or anyone with the
[INSERT|UPDATE|DELETE] ANY TABLE privileges or the ability to login to the application schema) from bypassing the application and modifying data directly. Generally speaking, your DBAs must be trusted individuals.