Before vs pre-images

From: Odba2003 <odba2003_at_aol.com>
Date: 01 Oct 2004 00:24:18 GMT
Message-ID: <20040930202418.17053.00001141@mb-m26.aol.com>

the question of before image vs pre-image has to do with Automatic Undo Management. Here is the context:

Oracle stores the before image of the data in special purpose UNDO tablespaces. Oracle also stores pre-images of data to enhance availability and read integrity for a query running in one session while another session is performing a dml transaction.

I guess my question is, are before images the same thing as pre-images? Received on Thu Sep 30 2004 - 19:24:18 CDT