Linux下安装Oracle后重启无法登录数据库ORA-01034:ORACLE not available

[root@root~]$ su - oracle

[oracle@localhost~]$ sqlplus

Connected to an idle instance.

enter username: /as sysdba

SQL>startup------------------启动数据库实例
Oracle instance started.
Total System Global Area *****bytes
Fixed Size *****bytes
Variable Size *****bytes
Database Buffers *****bytes
Redo Buffers *****bytes
Database mounted.
Database opened.

这样就能用啦