1.停库
[oracle@testdb ~]$ sqlplus / as sysdba
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> exit

2.停监听
[oracle@testdb ~]$ lsnrctl stop
LSNRCTL for Linux: Version 11.2.0.4.0 - Production on 23-DEC-2016 14:44:52
Copyright (c) 1991, 2013, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=testdb)(PORT=1521)))
The command completed successfully

3.停HTTP服务
[root@testdb ~]# service httpd stop
Stopping httpd: [ OK ]

4.用su或重新登录到root(如果重新安装可以保留oracle用户)

5.删除安装目录
[root@testdb ~]# rm -rf /u01/app/oracle/
[root@testdb ~]# rm -rf /u01/app/oraInventory/

6.删除/usr/bin下文件
[root@testdb ~]# rm -rf /usr/local/bin/dbhome
[root@testdb ~]# rm -rf /usr/local/bin/oraenv
[root@testdb ~]# rm -rf /usr/local/bin/coraenv

7.删除/etc/oratab
[root@testdb ~]# rm /etc/oratab

8.删除/etc/oraInst.loc
[root@testdb ~]# rm /etc/oraInst.loc

9.删除oracle用户(若要重新安装,可以不删除)
[root@testdb ~]# userdel -r oracle

10.删除用户组(若要重新安装,可以不删除)
[root@testdb ~]# groupdel oinstall
[root@testdb ~]# groupdel dba

11.删除启动服务
[root@testdb ~]# chkconfig
到此为止重启后，Linux系统下Oracle数据库已完全删除