Oracle 11g 安装完毕后，如果有卸载的需要。可以有如下方法：
1.手工删除Oracle安装时建立的各目录、文件等。这种方法对于Linux还算可行，但是Window版中涉及到服务、注册表等等。往往删除不干净。
2.使用安装目录$ORACLE_HOME/deinstall/下的 deinstall脚本。
[oracle@localhost deinstall]$ ./deinstall
Checking for required files and bootstrapping ...
Please wait ...
Location of logs /tmp/deinstall2015-08-22_00-06-37AM/logs/
############ ORACLE DEINSTALL & DECONFIG TOOL START ############
######################### CHECK OPERATION START #########################
## [START] Install check configuration ##
Checking for existence of the Oracle home location /u01/app/oracle/product/11.2.0/db_1
Oracle Home type selected for deinstall is: Oracle Single Instance Database
Oracle Base selected for deinstall is: /u01/app/oracle
Checking for existence of central inventory location /u01/app/oraInventory
Checking for sufficient temp space availability on node(s) : 'localhost.localdomain'
## [END] Install check configuration ##
Network Configuration check config START
Network de-configuration trace file location: /tmp/deinstall2015-08-22_00-06-37AM/logs/netdc_check2015-08-22_12-06-57-AM.log
Network Configuration check config END
Database Check Configuration START
Database de-configuration trace file location: /tmp/deinstall2015-08-22_00-06-37AM/logs/databasedc_check2015-08-22_12-07-12-AM.log
Use comma as separator when specifying list of values as input
Specify the list of database names that are configured in this Oracle home [orcl]:
###### For Database 'orcl' ######
Single Instance Database
The diagnostic destination location of the database: /u01/app/oracle/diag/rdbms/orcl
Storage type used by the Database: FS
Database file location: /u01/app/oracle/oradata/orcl,/u01/app/oracle/fast_recovery_area/orcl
Fast recovery area location: /u01/app/oracle/fast_recovery_area/ORCL
database spfile location: /u01/app/oracle/product/11.2.0/db_1/dbs/spfileorcl.ora
The details of database(s) orcl have been discovered automatically. Do you still want to modify the details of orcl database(s)? [n]:
Database Check Configuration END
Enterprise Manager Configuration Assistant START
EMCA de-configuration trace file location: /tmp/deinstall2015-08-22_00-06-37AM/logs/emcadc_check2015-08-22_12-07-52-AM.log
Checking configuration for database orcl
Enterprise Manager Configuration Assistant END
Oracle Configuration Manager check START
OCM check log file location : /tmp/deinstall2015-08-22_00-06-37AM/logs//ocm_check446.log
Oracle Configuration Manager check END
######################### CHECK OPERATION END #########################
####################### CHECK OPERATION SUMMARY #######################
Oracle Home selected for deinstall is: /u01/app/oracle/product/11.2.0/db_1
Inventory Location where the Oracle home registered is: /u01/app/oraInventory
The following databases were selected for de-configuration : orcl
Database unique name : orcl
Storage used : FS
No Enterprise Manager configuration to be updated for any database(s)
No Enterprise Manager ASM targets to update
No Enterprise Manager listener targets to migrate
Checking the config status for CCR
Oracle Home exists with CCR directory, but CCR is not configured
CCR check is finished
Do you want to continue (y - yes, n - no)? [n]: y
A log of this session will be written to: '/tmp/deinstall2015-08-22_00-06-37AM/logs/deinstall_deconfig2015-08-22_12-06-51-AM.out'
Any error messages from this session will be written to: '/tmp/deinstall2015-08-22_00-06-37AM/logs/deinstall_deconfig2015-08-22_12-06-51-AM.err'
######################## CLEAN OPERATION START ########################
Enterprise Manager Configuration Assistant START
EMCA de-configuration trace file location: /tmp/deinstall2015-08-22_00-06-37AM/logs/emcadc_clean2015-08-22_12-07-52-AM.log
Updating Enterprise Manager ASM targets (if any)
Updating Enterprise Manager listener targets (if any)
Enterprise Manager Configuration Assistant END
Database de-configuration trace file location: /tmp/deinstall2015-08-22_00-06-37AM/logs/databasedc_clean2015-08-22_12-08-27-AM.log
Database Clean Configuration START orcl
This operation may take few minutes.
Database Clean Configuration END orcl
Network Configuration clean config START
Network de-configuration trace file location: /tmp/deinstall2015-08-22_00-06-37AM/logs/netdc_clean2015-08-22_12-09-31-AM.log
De-configuring backup files...
Backup files de-configured successfully.
The network configuration has been cleaned up successfully.
Network Configuration clean config END
Oracle Configuration Manager clean START
OCM clean log file location : /tmp/deinstall2015-08-22_00-06-37AM/logs//ocm_clean446.log
Oracle Configuration Manager clean END
Setting the force flag to false
Setting the force flag to cleanup the Oracle Base
Oracle Universal Installer clean START
Detach Oracle home '/u01/app/oracle/product/11.2.0/db_1' from the central inventory on the local node : Done
Delete directory '/u01/app/oracle/product/11.2.0/db_1' on the local node : Done
Delete directory '/u01/app/oraInventory' on the local node : Done
Delete directory '/u01/app/oracle' on the local node : Done
Oracle Universal Installer cleanup was successful.
Oracle Universal Installer clean END
## [START] Oracle install clean ##
Clean install operation removing temporary directory '/tmp/deinstall2015-08-22_00-06-37AM' on node 'localhost'
## [END] Oracle install clean ##
######################### CLEAN OPERATION END #########################
####################### CLEAN OPERATION SUMMARY #######################
Successfully de-configured the following database instances : orcl
Cleaning the config for CCR
As CCR is not configured, so skipping the cleaning of CCR configuration
CCR clean is finished
Successfully detached Oracle home '/u01/app/oracle/product/11.2.0/db_1' from the central inventory on the local node.
Successfully deleted directory '/u01/app/oracle/product/11.2.0/db_1' on the local node.
Successfully deleted directory '/u01/app/oraInventory' on the local node.
Successfully deleted directory '/u01/app/oracle' on the local node.
Oracle Universal Installer cleanup was successful.
Run 'rm -rf /etc/oraInst.loc' as root on node(s) 'localhost' at the end of the session.
Run 'rm -rf /opt/ORCLfmap' as root on node(s) 'localhost' at the end of the session.
Run 'rm -rf /etc/oratab' as root on node(s) 'localhost' at the end of the session.
Oracle deinstall tool successfully cleaned up temporary directories.
#######################################################################
############# ORACLE DEINSTALL & DECONFIG TOOL END #############
在删除的过程中有以下几点需要确认的
Specify the list of database names that are configured in this Oracle home [orcl]:
指定需要删除的数据库名称，默认即可，直接回车。
The details of database(s) orcl have been discovered automatically. Do you still want to modify the details of orcl database(s)? [n]:
是否需要修改数据库的详细信息，默认n，直接回车。
Do you want to continue (y - yes, n - no)? [n]: y
是否继续，填写y，回车
脚本结尾，提示需要使用root用户删除如下三个脚本。
rm -rf /etc/oraInst.loc
rm -rf /opt/ORCLfmap
rm -rf /etc/oratab
至此，Oracle删除完毕。
将Oracle软件再次安装
./runInstaller -silent -responseFile /home/oracle/etc/install_software_only.rsp
3. 使用专用工具