When we perform an upgrade on Oracle we have two basically two options for binary or database engine.
- Use out-of-place Upgrade, this is to install another ORACLE_HOME binaries
- Use In-place Upgrade, this is to use the existing ORACLE_HOME.
The advantage of the first over the second is if you have to backtrack. We only would have to use the old binary (ORACLE_HOME previous to the upgrade), depending on the version of Oracle, run the script catalog.sql or script indicated by the version forback the upgrade to the previous version.
HTH – Antonio NAVARRO