Considerations for Basing a Partitioning Expression on a CASE_N Function
Building a partitioning expression on CASE_N is a reasonable thing to do only if the
following items are all true:
The partitioning expression defines a mapping between conditions and INTEGER numbers.
There are limited number of conditions (too many conditions can lead to excessive
CPU usage or the table header exceeding its maximum size limit).
Your query workloads against the table use equality conditions on the partitioning
columns to specify a single partition.
You have no need to alter the partitioning of the table.
You get the plans and data maintenance you need.