Info about installing cx_Oracle under OS X can be found at: https://gist.github.com/thom-nic/6011715
cx_Oracle must be installed because it doesn't come pre-installed with Python. Don't use pip! Instead of using pip, following the directions located here: http://joelvasallo.com/?p=276
When the instructions from the above link have been followed and completed, it is possible that you can update the cx_Oracle module with pip
sudo pip install --upgrade cx_Oracle