单项选择题 Youlosttheindextablespaceinyourdatabase.Youarenotabletousetablespacepoint­in­timerecoveryontheindextablespace.Whatcouldbethereasonforthis？（）

单项选择题 In your database， online redo log files are multiplexed and one of the members in a group is lost due to media failure.  How would you recover the lost redo log member？（）

单项选择题 A user executes a query on the EMP table， which contains thousands of rows， to get details about employees in one of the departments. The user receives the following error： SQL> SELECT ename FROM emp WHERE deptno=10 ORDER BY sal SELECT ename FROM emp WHERE deptno=10 ORDER BY sal  *  ERROR at line 1：  ORA­01157： cannot identify/lock data file 201 ­ see DBWR trace file  ORA­01110： data file 201： ’/u01/app/oracle/oradata/orcl/temp01.dbf’  What is a possible reason？（）