Oracle数据库状态

SQL> startup nomount;
ORACLE instance started.

Total System Global Area  125829120 bytes
Fixed Size                  1247684 bytes
Variable Size              92276284 bytes
Database Buffers          25165824 bytes
Redo Buffers                7139328 bytes

SQL> select status from v$instance;

STATUS
------------
STARTED

SQL> select open_mode from v$database;
select open_mode from v$database
*
ERROR at line 1:
ORA-01507: database not mounted

SQL> alter database mount;

Database altered.

SQL> select status from v$instance;

STATUS
------------
MOUNTED

SQL> select open_mode from v$database;

OPEN_MODE
----------
MOUNTED

SQL> alter database open;

Database altered.

SQL> select status from v$instance;

STATUS
------------
OPEN

SQL> select open_mode from v$database;

OPEN_MODE
----------
READ WRITE