152. One of the tablespaces is readonly in your database. The loss of all control files forced you to recreate the control file. Which operation do you need to perform after recreating the control file and opening the database?
A.drop and recreate the readonly tablespaces
B.rename the readonly data files to their correct file names
C.change the tablespace status from read/write to readonly
D.recreate the readonly tablespace because it is automatically removed
控制文件的备份与恢复在数据库的备份恢复过程中十分关键,其原则是:
在数据库物理结构发生变化后备份控制文件
方法有:
- 通过操作系统命令在数据库关闭时对控制文件进行copy,一般用于全库一致性恢复
- 利用alter database backup controlfile to 命令将控制文件备份到二进制文件中.oracle推荐使用这种方式来备份控制文件,这也是最简单的方式,比如:
- alter database backup controfile to '/home/oracle/control01.bak';
- 利用alter database backup controlfile to trace 命令将重建控制文件备份的脚本被分到后台的trace文件中.这种方式备份控制文件会丢失归档日志历史等许多信息.而且在重建控制文件时,只读表空间和脱机的数据文件的处理相对比较复杂.