1. What is the top most object type ?

My answer was dm_sysobject but the interviewer expected some other answer. Need help in this.

2. r_object_id - under which object type does it come? How and where it generated?

i explained r_object_id concept but the interviewer was specific abt its generation and its location of object type.

3.DQL to list active concurrent session?

Execute show_session was my answer. But the expectation was more.

4. Where does Documentum store cache files?

i didnt have answer.