使用dbca删除数据库或配置数据库选件时会遇到无法找到或找不了一个不是当前启动的数据库实例，如下所示：
[oracle@prodb-s ~]$ ps -ef |grep pmon
oracle 2002 32138 0 22:49 pts/3 00:00:00 grep pmon
oracle 32247 1 0 22:21 ? 00:00:00 ora_pmon_prodbca想要删除的实例名为pro，显示的却是prodb：
通常是因为没有规范的安装数据库导致/etc/oratab没有或信息不正确。
解决办法：
直接修改/etc/oratab中的实例和路径为正确的名称并重新执行dbca：
[oracle@prodb-s ~]$ cat /etc/oratab
#
# This file is used by ORACLE utilities. It is created by root.sh
# and updated by either Database Configuration Assistant while creating
# a database or ASM Configuration Assistant while creating ASM instance.
# A colon, ':', is used as the field terminator. A new line terminates
# the entry. Lines beginning with a pound sign, '#', are comments.
#
# Entries are of the form:
# $ORACLE_SID:$ORACLE_HOME:<N|Y>:
#
# The first and second fields are the system identifier and home
# directory of the database respectively. The third filed indicates
# to the dbstart utility that the database should , "Y", or should not,
# "N", be brought up at system boot time.
#
# Multiple entries with the same $ORACLE_SID are not allowed.
#
#
prodb:/u01/app/oracle/product/11.2.0/dbhome_1:N
