Audit parameter Audit_trail

The Audit_trail parameter defines where the audit record is stored by default db. If you set it to none, the standard database auditing feature is canceled. Audit_trail is a static parameter, and the database must be restarted after modification. The values that can be set:
-db: Open a database audit to write audit data to the database table sys.aud$ table
-db,extended: In addition to the audit content specified by the DB parameter, SQL with bound variables is audited
-xml: Turn on database auditing to write audit results to the operating system's XML-formatted file
-xml,extended: similar to db,extended
-os: Turn on database auditing to write audit results to operating system files

Audit parameter Audit_trail