The new release promises to deliver comprehensive features for Database administrators (DBAs) and developers. In order to make use of these features, databases need to be upgraded to Oracle Database 12c. Database upgrade assistant (DBUA) can be used by many Oracle DBAs as the upgrade process can be handled easily and finished quickly. In addition to the facts stated above, Oracle DBUA reduces the probability of wrong execution of scripts in the upgrade process and increases the ratio of successful upgrades. The choice of selecting the upgrading method can vary between companies according to their status and business criticality, database size, outage toleration, and technical expertise. These options support the updgrading from Oracle Database 11g to Oracle Database 12c. The chapter discusses database upgrade. All of the upgrade methods discussed help Oracle customers during the upgrade process.