I was searching over the internet to find good explanations of flashback, backup and checkpoint, but I find it hard to understand the difference.
Both flashback and backup can revert database to the previous state. Flashback can fix logical failures, but not physical failures.
Redo logs - store all changes made to the database, used to apply changes since latest backup
Checkpoint - when we update database, physical files aren't updated right away, but all changes are saved in redo logs to improve performance. Checkpoints are points when those changes are flushed to the database.
Sorry for my bad English. Could somebody explain those terms in more details ?