when you use auditing, you can see it (allthough not realtime)
depending on you security settings, but the most probable answer is that you web server is creating the connection to the oracle database and the end user only has his http connection to the web server. So, no with webi, you can’t see in oracle which user is connected (just that the webi server has a connection). Only when you use the BO user name to login to the database would you be able to see it.