I did the following :
alter system set compatible='8.1.7' scope=spfile;
when i start up the database again, i got the following error:
ORA-00402: database changes by release 18.104.22.168.0 cannot be used by release
ORA-00405: compatibility type "Locally Managed SYSTEM tablespace"
How do i set the compatible parameter to a lower version?? :confused: