human readable?redo log,roll back segment,archive

[khoshtip_uk]

1.are data in redo log file, archive logs,undo tbs ,rollback segment are human readable?

2. what happens to the data within rollback segment,undo tbs after some period of time ?will they be permanetly deleted? or are included in archive logfile?for point in time recovery?

3. does archive log include DDL? if not then what will happen if we delete all data from tbl1 on monday, set unique constraint on the table on tuesday and on wednesday try to do incomplete recovery to mondays date ( there used to be some duplicate entry in tbl1 on monday).

thanks