单项选择题
A. when you want to restore a table that has been dropped from the Recycle Bin
B. when you want to identify the transaction ID of the transaction that deleted some important records from a table
C. when you want to recover the schema of a dropped user
D.when you want to restore a dropped tablespace
单项选择题 YouareworkingasaDBAatNetFxCorporation.YoudiscoverthattheSCOTTschemaisdeletedbymistake.Youdecidetoflashthedatabasebacktothetimewhentheschemaexisted.Whichviewwillyouquerytodeterminetheestimatedsizeoftheflashbackdatathatyourequireforyourcurrenttargetretention？（）
单项选择题 YouhavejoinedaneworganizationasaDatabaseAdministrator.TheSecurityAdministratorinyourorganizationhaskepthumanerrors，suchaserroneouslydroppingusers，tables，andimportantdata，toaminimumbycarefullygrantingonlythenecessaryprivilegestoeachuser.Asaresultofseveralongoingtransactionswithinyourdatabase，youdiscoverthattheflashbacklogsarerapidlyincreasingintheflashrecoveryarea.Toavoidout-of-spaceerrors，youdecidetodeletetheflashbacklogsfromtheflashrecoveryarea.Howcanyoudeletetheflashbacklogsfromthedatabaseifyourdatabaseisupandrunning？（）
单项选择题 InwhichscenariodoyouusetheFlashbackDatabasefeature？（）