ORACLE的控制文件是数据库的非常重要的文件，它保存着数据库的连接实例(instance)和database的一个桥梁，它定义了当前数据库物理信息的状态。因此控制文件对于一个数据库来说是非常重要的，在某些时候我们需要重新创建控制文件：
 1。当控制文件丢失的时候，并且没有最近的文件Copy备份（一般在建库完成后的生成一个创建ControlFile的的脚本）。
2。需要修改数据库初始物理信息，如Log文件数量，数据文件的数量等，这些信息是在建库的时候写在ControlFIle里的，如果需要修改，可以通过重建ControlFile来调整。
以下是一种较好的重建控制文件的方法:
注：此方法应用在数据库可以mount起来但是不能open的情况下，该情况下是有控制文件的备份或控制文件出错，但可以把数据库mount起来，mount后才能执行alter trace的命令。
1. 在重建Contrl前，建议备份数据库中的数据，以防不测。
2. sqlplus /nolog
3. SQL>connect /as sysdba
4. SQL>alter database backup controlfile to trace; 备份创建控制文件的脚本到TRC文件
5. 在$ORACLE_HOME/admin/SID/udump下可找到最新生成的TRACE文件，如ora_23456.trc，此文件就包含了当前控制文件的参数及生成语法。
6. 提取ora_23456.trc中有关控制文件生成的语句另存为recreatctl.sql。
7. recreatctl.sql的内容为:
STARTUP NOMOUNT
CREATE CONTROLFILE REUSE DATABASE "ORCL" NORESETLOGS NOARCHIVELOG
MAXLOGFILES 32
MAXLOGMEMBERS 2
MAXDATAFILES 50
MAXINSTANCES 8
MAXLOGHISTORY 800
LOGFILE
GROUP 1 '/dev/vg00/roraredoa1' SIZE 10M,
GROUP 2 '/dev/vg00/roraredoa2' SIZE 10M,
GROUP 3 '/dev/vg00/roraredoa3' SIZE10M
DATAFILE
'/dev/vg00/rorclsys',
'/dev/vg00/rorclrbs',
'/dev/vg00/rorcltemp',
'/dev/vg00/rorcltools',
'/dev/vg00/rorcluser'
;
8. 如果需要修改，可按自己的需要编辑creatctl.sql中的参数，如maxdatafiles、maxinstances等。
9. sqlplus /nolog
10. SQL>connect /as sysdba
11. SQL>shutdown immediate
12. SQL>@recreatctl.sql
13. SQL>alter database open;
重新建控制文件完毕。
控制文件对于数据库来说是非常重要的数据结构，在进行数据恢复时通常是必不可少的.
Oracle提供两种方式备份控制文件:
 1.生成可以重建控制文件的脚本
2.备份二进制的控制文件
我们看一下如何获得可以重建控制文件的脚本.
 Oracle提供如下命令:
alter database backup controlfile to trace;
实际操作:
[oracle@standby tools]$ sqlplus "/ as sysdba"
SQL> alter database backup controlfile to trace;
Database altered.
SQL> @gettrcname
TRACE_FILE_NAME
--------------------------------------------------------------------------------
/opt/oracle/admin/primary/udump/primary_ora_2135.trc
trace文件内容:
[oracle@standby tools]$ more /opt/oracle/admin/primary/udump/primary_ora_2135.trc
/opt/oracle/admin/primary/udump/primary_ora_2135.trc
Oracle9i Enterprise Edition Release 9.2.0.4.0 – Production
With the Partitioning option
JServer Release 9.2.0.4.0 – Production
ORACLE_HOME = /opt/oracle/product/9.2.0
System name:    Linux
Node name:      standby
Release:        2.4.21-4.EL
Version:        #1 Fri Oct 3 18:13:58 EDT 2003
Machine:        i686
Instance name: primary
Redo thread mounted by this instance: 1
Oracle process number: 12
Unix process pid: 2135, image: oracle@standby (TNS V1-V3)
*** SESSION ID:(11.6) 2004-10-16 09:00:03.830
*** 2004-10-16 09:00:03.830
# The following are current System-scope REDO Log Archival related
# parameters and can be included in the database initialization file.

# LOG_ARCHIVE_DEST=''
# LOG_ARCHIVE_DUPLEX_DEST=''
#
# LOG_ARCHIVE_FORMAT=%t_%s.dbf
# REMOTE_ARCHIVE_ENABLE=TRUE
# LOG_ARCHIVE_START=TRUE
# LOG_ARCHIVE_MAX_PROCESSES=2
# STANDBY_FILE_MANAGEMENT=MANUAL
# STANDBY_ARCHIVE_DEST=?/dbs/arch
# FAL_CLIENT=''
# FAL_SERVER=''
#
# LOG_ARCHIVE_DEST_1='LOCATION=/opt/oracle/oradata/primary/archive'
# LOG_ARCHIVE_DEST_1='OPTIONAL REOPEN=300 NODELAY'
# LOG_ARCHIVE_DEST_1='ARCH NOAFFIRM SYNC'
# LOG_ARCHIVE_DEST_1='REGISTER NOALTERNATE NODEPENDENCY'
# LOG_ARCHIVE_DEST_1='NOMAX_FAILURE NOQUOTA_SIZE NOQUOTA_USED'
# LOG_ARCHIVE_DEST_STATE_1=ENABLE
#
# Below are two sets of SQL statements, each of which creates a new
# control file and uses it to open the database. The first set opens
# the database with the NORESETLOGS option and should be used only if
# the current versions of all online logs are available. The second
# set opens the database with the RESETLOGS option and should be used
# if online logs are unavailable.
# The appropriate set of statements can be copied from the trace into
# a script file, edited as necessary, and executed when there is a
# need to re-create the control file.
#
#     Set #1. NORESETLOGS case
#
# The following commands will create a new control file and use it
# to open the database.
# Data used by the recovery manager will be lost. Additional logs may
# be required for media recovery of offline data files. Use this
# only if the current version of all online logs are available.
STARTUP NOMOUNT
CREATE CONTROLFILE REUSE DATABASE "PRIMARY" NORESETLOGS  ARCHIVELOG
--  SET STANDBY TO MAXIMIZE PERFORMANCE
    MAXLOGFILES 5
    MAXLOGMEMBERS 3
    MAXDATAFILES 100
    MAXINSTANCES 1
    MAXLOGHISTORY 226
LOGFILE
  GROUP 1 '/opt/oracle/oradata/primary/redo01.log'  SIZE 10M,
  GROUP 2 '/opt/oracle/oradata/primary/redo02.log'  SIZE 10M,
  GROUP 3 '/opt/oracle/oradata/primary/redo03.log'  SIZE 10M
-- STANDBY LOGFILE
DATAFILE
  '/opt/oracle/oradata/primary/system01.dbf',
  '/opt/oracle/oradata/primary/undotbs01.dbf',
  '/opt/oracle/oradata/primary/users01.dbf'
CHARACTER SET ZHS16GBK
;
# Recovery is required if any of the datafiles are restored backups,
# or if the last shutdown was not normal or immediate.
RECOVER DATABASE
# All logs need archiving and a log switch is needed.
ALTER SYSTEM ARCHIVE LOG ALL;
# Database can now be opened normally.
ALTER DATABASE OPEN;
# Commands to add tempfiles to temporary tablespaces.
# Online tempfiles have complete space information.
# Other tempfiles may require adjustment.
ALTER TABLESPACE TEMP ADD TEMPFILE '/opt/oracle/oradata/primary/temp01.dbf'
     SIZE 41943040  REUSE AUTOEXTEND ON NEXT 655360  MAXSIZE 32767M;
# End of tempfile additions.
#
#     Set #2. RESETLOGS case
#
# The following commands will create a new control file and use it
# to open the database.
# The contents of online logs will be lost and all backups will
# be invalidated. Use this only if online logs are damaged.
STARTUP NOMOUNT
CREATE CONTROLFILE REUSE DATABASE "PRIMARY" RESETLOGS  ARCHIVELOG
--  SET STANDBY TO MAXIMIZE PERFORMANCE
    MAXLOGFILES 5
    MAXLOGMEMBERS 3
    MAXDATAFILES 100
    MAXINSTANCES 1
    MAXLOGHISTORY 226
LOGFILE
  GROUP 1 '/opt/oracle/oradata/primary/redo01.log'  SIZE 10M,
  GROUP 2 '/opt/oracle/oradata/primary/redo02.log'  SIZE 10M,
  GROUP 3 '/opt/oracle/oradata/primary/redo03.log'  SIZE 10M
-- STANDBY LOGFILE
DATAFILE
  '/opt/oracle/oradata/primary/system01.dbf',
  '/opt/oracle/oradata/primary/undotbs01.dbf',
  '/opt/oracle/oradata/primary/users01.dbf'
CHARACTER SET ZHS16GBK
;
# Recovery is required if any of the datafiles are restored backups,
# or if the last shutdown was not normal or immediate.
RECOVER DATABASE USING BACKUP CONTROLFILE
# Database can now be opened zeroing the online logs.
ALTER DATABASE OPEN RESETLOGS;
# Commands to add tempfiles to temporary tablespaces.
# Online tempfiles have complete space information.
# Other tempfiles may require adjustment.
ALTER TABLESPACE TEMP ADD TEMPFILE '/opt/oracle/oradata/primary/temp01.dbf'
     SIZE 41943040  REUSE AUTOEXTEND ON NEXT 655360  MAXSIZE 32767M;
# End of tempfile additions.
#
编辑这个trace文件,我们就可以获得创建控制文件的脚本.
根据数据库不同状况，你可以选择是使用RESETLOGS/NORESETLOGS来重建控制文件.
我们获得以下脚本:
[oracle@standby tools]$ cat createctlf.sql
STARTUP NOMOUNT
CREATE CONTROLFILE REUSE DATABASE "PRIMARY" NORESETLOGS  ARCHIVELOG
--  SET STANDBY TO MAXIMIZE PERFORMANCE
    MAXLOGFILES 5
    MAXLOGMEMBERS 3
    MAXDATAFILES 100
    MAXINSTANCES 1
    MAXLOGHISTORY 226
LOGFILE
  GROUP 1 '/opt/oracle/oradata/primary/redo01.log'  SIZE 10M,
  GROUP 2 '/opt/oracle/oradata/primary/redo02.log'  SIZE 10M,
  GROUP 3 '/opt/oracle/oradata/primary/redo03.log'  SIZE 10M
-- STANDBY LOGFILE
DATAFILE
  '/opt/oracle/oradata/primary/system01.dbf',
  '/opt/oracle/oradata/primary/undotbs01.dbf',
  '/opt/oracle/oradata/primary/users01.dbf'
CHARACTER SET ZHS16GBK
;
RECOVER DATABASE
ALTER SYSTEM ARCHIVE LOG ALL;
ALTER DATABASE OPEN;
ALTER TABLESPACE TEMP ADD TEMPFILE '/opt/oracle/oradata/primary/temp01.dbf'
     SIZE 41943040  REUSE AUTOEXTEND ON NEXT 655360  MAXSIZE 32767M;     

运行这个脚本即可重建控制文件:
[oracle@standby tools]$ sqlplus "/ as sysdba"
SQL*Plus: Release 9.2.0.4.0 - Production on Sat Oct 16 09:20:24 2004
Copyright (c) 1982, 2002, Oracle Corporation.  All rights reserved.
Connected to an idle instance.
SQL> set echo on
SQL> @createctlf
SQL> STARTUP NOMOUNT
ORACLE instance started.
Total System Global Area  135337420 bytes
Fixed Size                   452044 bytes
Variable Size             109051904 bytes
Database Buffers           25165824 bytes
Redo Buffers                 667648 bytes
SQL> CREATE CONTROLFILE REUSE DATABASE "PRIMARY" NORESETLOGS  ARCHIVELOG
  2  --  SET STANDBY TO MAXIMIZE PERFORMANCE
  3      MAXLOGFILES 5
  4      MAXLOGMEMBERS 3
  5      MAXDATAFILES 100
  6      MAXINSTANCES 1
  7      MAXLOGHISTORY 226
  8  LOGFILE
  9    GROUP 1 '/opt/oracle/oradata/primary/redo01.log'  SIZE 10M,
 10    GROUP 2 '/opt/oracle/oradata/primary/redo02.log'  SIZE 10M,
 11    GROUP 3 '/opt/oracle/oradata/primary/redo03.log'  SIZE 10M
 12  -- STANDBY LOGFILE
 13  DATAFILE
 14    '/opt/oracle/oradata/primary/system01.dbf',
 15    '/opt/oracle/oradata/primary/undotbs01.dbf',
 16    '/opt/oracle/oradata/primary/users01.dbf'
 17  CHARACTER SET ZHS16GBK
 18  ;
Control file created.
SQL> RECOVER DATABASE
ORA-00283: recovery session canceled due to errors
ORA-00264: no recovery required
SQL> ALTER SYSTEM ARCHIVE LOG ALL;
System altered.
SQL> ALTER DATABASE OPEN;
Database altered.
SQL> ALTER TABLESPACE TEMP ADD TEMPFILE '/opt/oracle/oradata/primary/temp01.dbf'
  2       SIZE 41943040  REUSE AUTOEXTEND ON NEXT 655360  MAXSIZE 32767M;
Tablespace altered.
SQL>      

以上给出生成创建控制文件脚本并重建控制文件的方法，但是具体恢复中遇到的问题可能需要具体对待.
这种方法通常是在没有控制文件(二进制文件)备份的情况下所采用的，如果存在备份应该使用备份的控制文件尝试恢复.