1) What is exactly internal. Why password of internal is oracle and sys change_on_install. Can we change their passwords and if by changing one does the other's password also set to same.
2) system and sys are users. Is sys higher than system. If so, in what all ways. Is DBA the only role granted to system and what all are granted to sys.
3) sysdba and then sysoper are the top most authorities in oracle. Does this mean they have been assigned roles and privileges more than those granted to any user.
4) We can grant dba to any user if connected as sys or system. Can we grant sysdba/sysoper to any user and if so connected as what user.
5) connect / as sysdba is the highest connection?
6) Can we do exactly the same things when connected as internal/oracle@mydb and sys/mypwd@mydb OR internal/oracle as sysdba and sys/mypwd as sysdba.
7) connect system/manager as sysdba. Does this mean system is a sysdba now?
8) If we grant roles and privileges to a user and if a particular role is having some privileges separately granted. Now, if we revoke the role do we revoke the privileges that were granted separately also.