I observed a different behavior between version 1.2.1 and 2.3.2 (that's the only two versions I've been able to test).
When creating an external table pointing to ORC files and having upper cased column names in the ORC files metadata I'm able to read the data on 1.2.1 but not on 2.3.2.
I tested with both upper cased and lower cased column names in my CREATE TABLE statement and it does not work in both cases. Looks like normal since column names are normalized to lower case in Hive.
So, I would like to know if this is a feature or a bug in Hive 2.3.2 ?
In fact, if this is a feature it would be impossible to have upper case column names in ORC files with Hive 2.3.2.
Please, let me know if you need more informations.