多选题Which operations require undo data（）ACommitting a transactionBFlashing back a transactionCRecovering a failed transactionDRunning a read-consistent queryEChanging a tablespace status from READ ONLY to READ WRITE
题目
多选题
Which operations require undo data（）
A
Committing a transaction
B
Flashing back a transaction
C
Recovering a failed transaction
D
Running a read-consistent query
E
Changing a tablespace status from READ ONLY to READ WRITE