The DEDB process in the second phase of a two-phase commit process if the chosen action is COMMIT. For DEDBs, if phase two action is COMMIT, the changes are written to the database using REDO, because the DEDB changes have only been made in main storage. If the action is BACKOUT, no changes are required to the database because the updates are still in main storage. The process applied is called UNDO. REDO is also used to refer to the action required for committed DEDBs during emergency restart of IMS, DL/I, or SQL/DS.