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

          比如，OCP_043有道题目：

3. One of the tablespace is read-only in your database. The loss of all 
control file forced you to recreate the control file. Which operation do 
you need to perform after re-creating the control file and opening the 
database? 

A. Drop and re-create the read-only tablespaces 
B. Rename the read-only data file to their correct file names. 
C. Change the tablespace status from read/write to read-only. 
D. Re-create the read-only tablespace because it is automatically removed.
 
Answer: B 

          oradebug必须以SYSDBA形式登陆后方能使用，可参看：oradebug使用介绍

idle> conn / as sysdba
Connected.
sys@ORCL> oradebug setmypid
Statement processed.
sys@ORCL> oradebug dump controlf 3;    
Statement processed.
sys@ORCL> oradebug tracefile_name;
/u01/app/oracle/admin/orcl/udump/orcl_ora_7489.trc

       ㈢ OCP考题

4. You backed up the control file to trace. Which statement is true about the trace file generated? 

A. The trace file is in binary format. 
B. The trace file has a SQL scripts to re-create the control file. 
C. The trace file is a backup set created during the backup of the control file. 
D. The trace file contains the instructions to manually re-create the control file. 
E. The trace file is an image copy of the control file created during the backup of 
the the control file. 

answer： B