一、问题描述：单位一套测试Oracle数据库，本想用DBCA看看数据库配置信息，当然也是手闲得慌，谁想到竟然出现下面的画面。创建新的数据，配置数据库操作按键是灰色，不让点击。这是什么情况，实例没有启动，不可能啊 ，刚刚还登录过呢。好吧，开始处理过程之旅。
二、处理方法：
1. 检查/etc/oratab文件 ，发现关于路径的信息都是之前安装的ORACLE软件目录（/u01/.....）与现在的软件目录（/home/oracle/app/.....）不一致。
修改前：
[oracle@tora01 etc]$ cat 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::
#
# 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 $ORACLE_SID are not allowed.
#
#
holytest:/u01/app/oracle/product/11.2.0/db_1:N
修改后：
[oracle@tora01 etc]$ cat 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::
#
# 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.
#
#
holytest:/home/oracle/app/oracle/product/11.2.0/dbhome_1:N
2. 再次启动DBCA进行验证，发现恢复正常
三、总结：一次小小的发现，对oratab文件的了解又深入了一点点。该文件最后那个N，如果你需要数据自动启动的话，要改为Y，这些都是经验啊，还要继续努力学习。