控制文件(control file)是一个相当小的文件(最多能增长到64M左右),其中包含Oracle需要的其他文件的一个目录。参数文件告知实例控制文件的位置,控制文件则告知示例数据库和在线重做日志文件的位置。控制文件还告知了Oracle其他一些事情,如已发生检查点的有关信息、数据库名(必须和db_name参数匹配)、创建数据库的时间戳、归档重做日志的历史(有时这会让控制文件变大)、RMAN信息等。
控制文件应该通过硬件(RAID)多路保存,如果不支持镜像,则要通过Oracle多路保存。应该有不止一个副本,而且它们应该保存在不同的磁盘上,以防止万一出现磁盘故障而丢失控制文件。丢失控制文件并不是致命的,但是会使恢复变得困难很多。
如果丢失了所有的控制文件并且没有任何的备份,我们可以通过重建控制文件来打开数据库。其中,重建控制文件至少需要以下信息:
1.数据库名
2.字符集
3.数据文件名称
4.初始化参数,包括MAXLOGFILES、MAXLOGMEMBERS、MAXDATAFILES、MAXINSTANCES、MAXLOGHISTORY等;
1.环境准备
数据库版本
我们在Oracle11g中进行测试。
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SQL >
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SQL > select * from v$version ;
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BANNER
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--------------------------------------------------------------------------------
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Oracle Database 11g Enterprise Edition Release 11 . 2 . . 3 . 0 - Production
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PL / SQL Release 11 . 2 . . 3 . 0 - Production
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CORE 11 . 2 . . 3 . 0 Production
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TNS for Linux : Version 11 . 2 . . 3 . 0 - Production
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NLSRTL Version 11 . 2 . . 3 . 0 - Production
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SQL >
删除控制文件
1.通过查询control_files初始化参数,获取控制文件路径;
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SQL >
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SQL > show parameter control_files
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NAME TYPE VALUE
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------------------------------------ ----------- ------------------------------
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control_files string / u01 / app / oracle / oradata / HOEGH /
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control01 . ctl , / u01 / app / oracle
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/ oradata / HOEGH / control02 . ctl
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SQL >
2.然后,使用rm命令删除控制文件;
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[ oracle @ HOEGH ~ ] $ rm / u01 / app / oracle / oradata / HOEGH / control01 . ctl
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[ oracle @ HOEGH ~ ] $ rm / u01 / app / oracle / oradata / HOEGH / control02 . ctl
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[ oracle @ HOEGH ~ ] $
3.此时,强制关闭数据库,然后重启数据库,报ORA-00205错误。需要注意的是,此时执行shutdown immediate命令,数据库无法正常关闭,只能关闭到mounted状态;需要使用shutdown abort命令强制关闭数据库。
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SQL >
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SQL > shutdown immediate
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Database closed .
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ORA - 00210 : cannot open the specified control file
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ORA - 00202 : control file : \ '/u01/app/oracle/oradata/HOEGH/control01.ctl\'
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ORA - 27041 : unable to open file
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Linux Error : 2 : No such file or directory
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Additional information : 3
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SQL > select status from v$instance ;
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STATUS
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------------
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MOUNTED
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SQL >
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SQL > shutdown abort
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ORACLE instance shut down .
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SQL >
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SQL >
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SQL > startup
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ORACLE instance started .
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Total System Global Area 941600768 bytes
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Fixed Size 1348860 bytes
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Variable Size 515902212 bytes
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Database Buffers 419430400 bytes
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Redo Buffers 4919296 bytes
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ORA - 00205 : error in identifying control file , check alert log for more info
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SQL >
2.获取数据库名
首先生成文本格式的参数文件;
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SQL >
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SQL > create pfile from spfile ;
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File created .
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SQL >
打开参数文件,查看db_name参数值,即为数据库名称。
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[ oracle @ hoegh dbs ] $ cat initHOEGH . ora
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HOEGH . __db_cache_size = 419430400
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HOEGH . __java_pool_size = 4194304
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HOEGH . __large_pool_size = 4194304
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HOEGH . __oracle_base = \ '/u01/app/oracle\' # ORACLE_BASE set from environment
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HOEGH . __pga_aggregate_target = 377487360
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HOEGH . __sga_target = 566231040
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HOEGH . __shared_io_pool_size =
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HOEGH . __shared_pool_size = 130023424
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HOEGH . __streams_pool_size =
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* . audit_file_dest = \ '/u01/app/oracle/admin/HOEGH/adump\'
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* . audit_trail = \ 'db\'
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* . compatible = \ '11.2.0.0.0\'
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* . control_files = \ '/u01/app/oracle/oradata/HOEGH/control01.ctl\' , \ '/u01/app/oracle/oradata/HOEGH/control02.ctl\'
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* . db_block_size = 8192
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* . db_domain = \ '\'
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* . db_name = \ 'HOEGH\'
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* . diagnostic_dest = \ '/u01/app/oracle\'
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* . dispatchers = \ '(PROTOCOL=TCP) (SERVICE=HOEGHXDB)\'
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* . memory_max_target = 943718400
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* . memory_target = 943718400
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* . open_cursors = 300
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* . processes = 150
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* . remote_login_passwordfile = \ 'EXCLUSIVE\'
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* . undo_tablespace = \ 'UNDOTBS1\'
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[ oracle @ hoegh dbs ] $
3.启动到nomount状态,获取字符集
由于需要执行查询语句select userenv('language') from dual;来获取字符集,因此需要将数据库启动到nomount状态。
点击( 此处 )折叠或打开
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SQL >
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SQL > startup nomount
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ORACLE instance started .
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Total System Global Area 941600768 bytes
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Fixed Size 1348860 bytes
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Variable Size 515902212 bytes
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Database Buffers 419430400 bytes
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Redo Buffers 4919296 bytes
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SQL >
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SQL > select userenv ( \ 'language\' ) from dual ;
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USERENV ( \ 'LANGUAGE\' )
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----------------------------------------------------
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AMERICAN_AMERICA . US7ASCII
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SQL >
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SQL >
4.获取数据文件名称
通过ls命令获取数据文件列表。
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[ oracle @ hoegh HOEGH ] $ ls - lh
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total 1 . 8G
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- rw - r ----- 1 oracle oinstall 314M May 30 11:07 example01.dbf
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- rw - r ----- 1 oracle oinstall 51M May 30 11:07 redo01.log
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- rw - r ----- 1 oracle oinstall 51M May 30 11:07 redo02.log
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- rw - r ----- 1 oracle oinstall 51M May 30 11:07 redo03.log
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- rw - r ----- 1 oracle oinstall 541M May 30 11:07 sysaux01.dbf
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- rw - r ----- 1 oracle oinstall 721M May 30 11:07 system01.dbf
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- rw - r ----- 1 oracle oinstall 30M Oct 13 2014 temp01.dbf
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- rw - r ----- 1 oracle oinstall 96M May 30 11:07 undotbs01.dbf
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- rw - r ----- 1 oracle oinstall 5.1M May 30 11:07 users01.dbf
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[ oracle @ hoegh HOEGH ] $
5.生成创建控制文件脚本
这样,创建控制文件所需的基本信息都已经有了,我们来生成创建控制文件脚本。
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STARTUP NOMOUNT
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CREATE CONTROLFILE REUSE DATABASE \ "HOEGH\" NORESETLOGS ARCHIVELOG
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MAXLOGFILES 5
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MAXLOGMEMBERS 3
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MAXDATAFILES 100
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MAXINSTANCES 1
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MAXLOGHISTORY 226
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LOGFILE
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GROUP 1 \ '/u01/app/oracle/oradata/HOEGH/redo01.log\' SIZE 50M ,
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GROUP 2 \ '/u01/app/oracle/oradata/HOEGH/redo02.log\' SIZE 50M ,
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GROUP 3 \ '/u01/app/oracle/oradata/HOEGH/redo03.log\' SIZE 50M
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DATAFILE
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\ '/u01/app/oracle/oradata/HOEGH/system01.dbf\' ,
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\ '/u01/app/oracle/oradata/HOEGH/sysaux01.dbf\' ,
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\ '/u01/app/oracle/oradata/HOEGH/undotbs01.dbf\' ,
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\ '/u01/app/oracle/oradata/HOEGH/users01.dbf\' ,
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\ '/u01/app/oracle/oradata/HOEGH/example01.dbf\' ,
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\ '/u01/app/oracle/oradata/HOEGH/temp01.dbf\'
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CHARACTER SET US7ASCII
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;
6.重建控制文件
需要注意的是,在执行上述创建脚本时会报错,系统提示临时文件不属于数据文件,如下所示:
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SQL > @ / u01 / app / oracle / oradata / HOEGH / CreateControlFile . sql
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ORA - 01081 : cannot start already - running ORACLE - shut it down first
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CREATE CONTROLFILE REUSE DATABASE \ "HOEGH\" NORESETLOGS ARCHIVELOG
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*
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ERROR at line 1 :
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ORA - 01503 : CREATE CONTROLFILE failed
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ORA - 01160 : file is not a data file
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ORA - 01110 : data file : \ '/u01/app/oracle/oradata/HOEGH/temp01.dbf\'
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SQL >
修改脚本并重新执行,重建控制文件后,数据库会打开到mount状态。
点击( 此处 )折叠或打开
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SQL >
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SQL > @ / u01 / app / oracle / oradata / HOEGH / CreateControlFile . sql
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ORACLE instance started .
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Total System Global Area 941600768 bytes
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Fixed Size 1348860 bytes
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Variable Size 515902212 bytes
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Database Buffers 419430400 bytes
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Redo Buffers 4919296 bytes
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Control file created .
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SQL >
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SQL > select status from v$instance ;
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STATUS
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MOUNTED
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SQL >
7.打开数据库
在打开数据库时,会报错,提示system01数据文件需要执行介质恢复,我们执行recover database即可。
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SQL >
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SQL > alater database open ;
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SP2 - 0734 : unknown command beginning \ "alater dat...\" - rest of line ignored .
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SQL >
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SQL > alter database open ;
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alter database open
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*
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ERROR at line 1 :
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ORA - 01113 : file 1 needs media recovery
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ORA - 01110 : data file 1 : \ '/u01/app/oracle/oradata/HOEGH/system01.dbf\'
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SQL >
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SQL > recover database ;
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Media recovery complete .
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SQL >
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SQL > alter database open ;
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Database altered .
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SQL >
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SQL > select * from v$version ;
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BANNER
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--------------------------------------------------------------------------------
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Oracle Database 11g Enterprise Edition Release 11 . 2 . . 3 . 0 - Production
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PL / SQL Release 11 . 2 . . 3 . 0 - Production
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CORE 11 . 2 . . 3 . 0 Production
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TNS for Linux : Version 11 . 2 . . 3 . 0 - Production
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NLSRTL Version 11 . 2 . . 3 . 0 - Production
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SQL >
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SQL> select tablespace_name from dba_tablespaces; TABLESPACE_NAME
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SYSTEM
SYSAUX
UNDOTBS1
TEMP
USERS
EXAMPLE 6 rows selected. SQL>
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8.总结
下面总结一下重建控制文件的步骤:
1.获取数据库名;
2.获取字符集名;
3.获取数据文件名;
4.重建控制文件;
5.执行介质恢复;
6.打开数据库。
hoegh
15.05.30
-- The End --
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