Will try
My understandings are
Database Rollback.
In some systems like Oracle (I believe) you have two options available after a transaction has been run. The transaction has in effect created a shadow set of the data
Option 1 is to Commit. This permanently changes the records basically to those shown in the shadow set of data
Option 2 Is Rollback. This is effectively an UNDO. Basically the records are not changed and the shadow set is dumped.
Database Recovery
It has crashed for whatever reason and this is basically about recovering the application into a condition whereby it will run and the data is as it was at a certain date and time
HTH
Len B
