If sessions are not persistent (that is, they connect, run SQL, and disconnect), then combining a logon trigger with setting the client identifier may enable you to pinpoint a specific user or group of users. Figure 5-20 shows a working logon trigger used for just such an occasion.

Figure 5-20. This actual working logon trigger can be used as a template to set a session's client identifier based on an amazing array of possibilities.

There is a lot to glean from Figure 5-20. First, remember that if the application uses a TP monitor or Oracle connections are persistent, then this approach is not likely to work. The first time the persistent connection is made, its client identifier will be set and cannot be reset by a logon trigger. Perhaps somewhere else in the application, or through your methods, the client identifier will be reset, but obviously the logon trigger is fired only once for each session.