The number of Oracle license is required is based on the usage and business environment. Take for example, Oracle database EE during the testing, staging and production phase. Depending on the type of license being used, their number of different Oracle licenses required.
If you’re licensing by processor, the number of Oracle licenses would be dependent on where the database is installed or running must be licensed. So, you have 6 processors, you need 6 licenses. If you have 20 processors installed, but only five of them are actually running, you still need 20 licenses.
If you’re using the Named User Plus scenario, there is a formula that can be used to compute how many Oracle licenses are needed. The formula would be Named User Plus — meaning 25 Named User Plus licenses per processor — multiplied by the number of actual users accessing the database. Now, the actual users mean the number of users and developers.