1.启动例程
conn sys/sys as sysdba startup nomount
2.nomount 状态转为mount状态
alter database mount; alter database open;
3.启动例程并装载数据库
startup mount
4.启动例程装载并打开数据库
startup open
5.以受限模式打开数据库
startup restrict
6.以只读模式打开数据库
conn sys/sys as sysdba shutdown immediate startup mount alter database open read only; update scott.emp set sal=1000 where empno=70;