多选题Which two are prerequisites for performing a flashback transaction?（）AFlashback Database must be enabled.BUndo retention guarantee for the database must be configured.CEXECUTE privilege on the DBMS_FLASHBACK package must be granted to the user flashing
题目
多选题
Which two are prerequisites for performing a flashback transaction?（）
A
Flashback Database must be enabled.
B
Undo retention guarantee for the database must be configured.
C
EXECUTE privilege on the DBMS_FLASHBACK package must be granted to the user flashing back transaction.
D
Supplemental logging must be enabled.
E
Recycle bin must be enabled for the database.
F
Block change tracking must be enabled tor the database.