（96）Examine the following command:

SQL>ALTER TABLE booking SHRINK SPACE COMPACT;

Which activity is performed when the preceding command is executed?

A. The shrink operation touches every block in the BOOKING table

B. The high-water mark(HWM)for the BOOKING table is shifted from its original position

C. The progress of the shrink operation is saved in the bitmap blocks of the BOOKING table

D. The data manipulation language(DML)triggers on the BOOKING table are executed because the shrink operation is internally handled by the INSERT/DELETE operation

答案：（C）

解析：

ALTER TABLE...SHRINK SPACE COMPACT

COMPACT, Oracle只是defragment段空间并压缩表行.数据库并不调整HWM,也不立即释放空间.

                需要后面再执行另一个ALTER TABLE...SHRINK SPCACE语句来释放空间.

                该选项用于以2个短的步骤而不是一个长的步骤来完成shrink操作.