thanks for adding notes here.It is meaningful for those who are taking auditing/accounting subjects. Hope you may upload more notes in the future.

Auditing is the monitoring and recording of configured database actions, from both database users and nondatabase users.

"Nondatabase users" refers to application users who are recognized in the database using the CLIENT_IDENTIFIER attribute. To audit this type of user, you can use a unified audit policy condition, a fine-grained audit policy, or Oracle Database Real Application Security.

You can base auditing on individual actions, such as the type of SQL statement executed, or on combinations of data that can include the user name, application, time, and so on.

You can configure auditing for both successful and failed activities, and include or exclude specific users from the audit. In a multitenant environment, you can audit individual actions of the pluggable database (PDB) or individual actions in the entire multitenant container database (CDB). In addition to auditing the standard activities the database provides, auditing can include activities from Oracle Database Real Application Security, Oracle Recovery Manager, Oracle Data Pump, Oracle Data Mining, Oracle Database Vault, Oracle Label Security, and Oracle SQL*Loader direct path events.

Auditing is enabled by default. All audit records are written to the unified audit trail in a uniform format and are made available through the UNIFIED_AUDIT_TRAIL view. These records reside in the AUDSYS schema. The audit records are stored in the SYSAUX tablespace by default. Oracle recommends that you configure a different tablespace for the unified audit trail. Be aware that for most Oracle Database editions except for Enterprise Edition, you can only associate the tablespace for unified auditing once. You should perform this association before you generate any audit records for the unified audit trail. After you have associated the tablespace, you cannot modify it because partitioning is only supported on Enterprise Edition.