This figure illustrates an environment in which you can audit the client identifier of a user. From left to right, top to bottom, top to bottom, are the following components:
A client connects to a mid-tier application called AppHR.
The AppHR mid-tier application passes the user's authentication to the first database, Database 1. The AppHR application sets the client identifier to CLIENT_A.
From Database 1, you can audit the client identifier CLIENT_A by querying the CLIENT_ID column of the DBA_AUDIT_TRAIL view.
A database link connects Database 1 to a second database, Database 2. The user now has connected to Database 2.
From Database 2, you can audit the client identifer again, by querying the CLIENT_ID column of the DBA_AUDIT_TRAIL view.