Hi TheKing,
Assuming the following:

1) your installation of ALM is current and patched to a level that supports Oracle 12c
2) you do not change anything about the installation during the upgrade (ip address, name, location, permissions of users, port or any settings on the Oracle DB)
3) you stop the ALM application server prior to the upgrade
4) you are properly backed up of the repositories and the DB components (as a safety measure in case you need to recover)

You shouldn't have to change anything and once the upgrade is completed then nothing else should need to be changed and restarting the application server/ services once the DB server is up and running should yield a fully functioning application.

Hope this helps,
Dan

Hi HiomerJ,
We are not standing up another Oracle DB and then migrating everything from your current Oracle DB to the new Oracle DB. So, we are just upgrading the versions in the current location

DBA team planning to upgrade oracle version from 11g to 12c. And we just want to make sure HP ALM/QC is still up and running and there is no downtime. I want to know if we need to do anything before or after the oracle version upgrade. For example, do we need to update the dbid.xml files etc.

Thank you.