1. Stop using Oracle services
Disable the oracle service, enter computer management, find all services starting with oracle in the service, right-click and select stop.
2. Open the Universal Installer tool to run the uninstall Oracle database program
(1) In general, run the uninstall program that comes with Oracle, such as using the Universal Installer tool to uninstall.
Click the Start menu to find Oracle, then click Oracle to install the product, and then click Universal Installer.
(2) After clicking, wait for a while and then enter the following interface, click to uninstall the product
(3) Select the Oracle product to be deleted, and then click Delete
(4) Enter the directory shown in the figure below, find the install file and run it to delete it.
(5) After finding the deinstall.bat file, double-click
3. Enter the uninstall batch program to run the uninstall
(1) Appears -- specify all single-instance listeners to be unconfigured [LISTENER]: Enter LISTENER as shown in the figure --- then press Enter
(2) Enter the following interface after pressing Enter
At this time, enter the content within [], and use English commas as separators when specifying multiple lists. In this example, there is only one ORCLS, so just enter ORCLS and press Enter
Remember not to do anything after pressing Enter---wait patiently until the content in the next step appears
If input is made at this time, it will enter the buffer as the input of the following options
If the content of the next step of friends is different from mine, please uninstall again
(3), appear ------ specify the type of this database (1. single instance database | 2. database with Oracle Restart enabled) [1]: press Enter directly
(4), appears ------ the diagnostic target location of the specified database [D:\APP\ADMINISTRATOR\diag\rdbms\orcls]: press Enter directly
(5) If the information shown in the red box prompts that the directory does not exist, then specify the directory as D:\APP\ADMINISTRATOR\diag
Where D:\APP\ADMINISTRATOR\ is the directory where you installed Oracle
实在不知道的同学直接复制指定数据库的诊断目标位置 [D:\APP\ADMINISTRATOR\diag\rdbms\orcls]:中的D:\APP\ADMINISTRATOR\diag然后回车即可
（6）、出现------指定数据库 ASM|FS 使用的存储类型 [FS]: 输入FS回车
（7）出现------如果有任何数据库文件存在于共享文件系统上, 请指定目录的列表。如果找到了 'ORCLS' 子目录, 则将删除该子目录。
否则将删除指定的目录。此外, 可以指定可以指定带有完整路径的数据库文件的列表直接回车
（8）、如果在文件系统上配置了快速恢复区, 请指定其位置。如果找到了 'ORCLS' 子目录, 则将删除该子目录。
直接回车
（9）出现------指定数据库 spfile 位置
直接回车
（10）出现------是否继续 输入y回车
这里在CMD里面的操作就完成了，静静等待CMD页面自动消失即可
四、删除注册表中Oracle相关项
（1）、本例中的Oracle的安装目录为D:\app如下图，朋友们可以进入如下红框的路径
（3）、Win+R打开运行界面，输入regedit，回车进入注册表编辑器
删除HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\路径下的所有Oracle开始的服务名称.
（3）删除HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Eventlog\Application注册表的所有Oracle开头的所有
（4）删除HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE 注册表
五、删除Oracle环境变量
右键点击我的电脑-->属性-->高级-->环境变量,删除环境变量ORACLE_HOME、TNS_ADMIN等环境变量，删除PATH中等环境变量有关Oracle的设定的路径信息
然后查看环境变量中是否存在Oracle相关的设置，若有直接删除与Oracle有关的设置
我的环境变量里没有相关设置就不截图了
六、删除Oracle安装目录、文件
（1）、删除D:\app目录下的所有文件
（2）、删除C盘下C:\Program Files或者C:\Program Files(x86)目录下的Oracle目录如下图
然后重启电脑，至此,Oracle已经完全卸载了嘻嘻，下面就可以重装了。~~~~~~~~~