| OS_USERNAME | VARCHAR2(255) |  | Operating system login username of the user whose actions were audited | 
| USERNAME | VARCHAR2(30) |  | Name (not ID number) of the user whose actions were audited | 
| USERHOST | VARCHAR2(128) |  | Client host machine name | 
| TERMINAL | VARCHAR2(255) |  | Identifier of the user's terminal | 
| TIMESTAMP | DATE |  | Date and time of the creation of the audit trail entry (date and time of user login for entries created by AUDIT SESSION) in the local database session time zone | 
| ACTION_NAME | VARCHAR2(28) |  | Name of the action type corresponding to the numeric code in the ACTIONcolumn inDBA_AUDIT_TRAIL | 
| LOGOFF_TIME | DATE |  | Date and time of user log off | 
| LOGOFF_LREAD | NUMBER |  | Logical reads for the session | 
| LOGOFF_PREAD | NUMBER |  | Physical reads for the session | 
| LOGOFF_LWRITE | NUMBER |  | Logical writes for the session | 
| LOGOFF_DLOCK | VARCHAR2(40) |  | Deadlocks detected during the session | 
| SESSIONID | NUMBER | NOT NULL | Numeric ID for each Oracle session | 
| RETURNCODE | NUMBER | NOT NULL | Oracle error code generated by the action. Some useful values: | 
| CLIENT_ID | VARCHAR2(64) |  | Client identifier in each Oracle session | 
| SESSION_CPU | NUMBER |  | Amount of CPU time used by each Oracle session | 
| EXTENDED_TIMESTAMP | TIMESTAMP(6) WITH TIME ZONE |  | Timestamp of the creation of the audit trail entry (timestamp of user login for entries created by AUDIT SESSION) in UTC (Coordinated Universal Time) time zone | 
| PROXY_SESSIONID | NUMBER |  | Proxy session serial number, if an enterprise user has logged in through the proxy mechanism | 
| GLOBAL_UID | VARCHAR2(32) |  | Global user identifier for the user, if the user has logged in as an enterprise user | 
| INSTANCE_NUMBER | NUMBER |  | Instance number as specified by the INSTANCE_NUMBERinitialization parameter | 
| OS_PROCESS | VARCHAR2(16) |  | Operating System process identifier of the Oracle process |