（669）User SCOTT wants to back out the transactions on the REGIONS table in his schema.As a DBA,

which commands must you execute to enable SCOTT to flash back the transactions?(Choose four.)

A. ALTER DATABASE FLASHBACK ON;

B. GRANT SELECT ANY TRANSACTION TO scott;

C. GRANT EXECUTE ON dbms_flashback TO scott;

D. ALTER DATABASE ADD SUPPLEMENTAL LOG DATA;

E. ALTER TABLESPACE undots1 RETENTION GUARANTEE;

F. ALTER DATABASE ADD SUPPLEMENTAL LOG DATA(PRIMARY KEY)COLUMNS;

答案：（B、C、D、F）

解析：

B，scott用户想闪回事务，先要能够有查询flashback_transaction_query表的权限

C，要能够闪回事务，需要调用DBMS_FLASHBACK.TRANSACTION_BACKOUT的存储过程实现

D，为了能够跟踪外键依赖还需要启用外键补充日志；同时也要把SUPPLEMENTAL LOG打开

F，为了该功能可以正常使用，至少需要事先启用主键补充日志

启用外键补充日志的语句是：alter database add/drop supplemental log data(foreign key)columns，请大家注意）

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Oracle 11G OCP 1Z0-053 669