oracle status

1、SQL>startup mount

数据库进入mount状态，只可以读取控制文件信息，不可以读取数据文件信息；

2、SQL>alter database open

将数据库切换到open状态

3、查询数据库状态

SQL> select dbid,name,switchover_status,db_unique_name,database_role,open_mode,current_scn from v$database;

      DBID NAME      SWITCHOVER_STATUS    DB_UNIQUE_NAME                 DATABASE_ROLE    OPEN_MODE            CURRENT_SCN
---------- --------- -------------------- ------------------------------ ---------------- -------------------- -----------
 724433656 DEVDB     TO PRIMARY           phydb                          PHYSICAL STANDBY MOUNTED                  1545869

4、查看监听服务的状态

11gdg-> id
uid=1101(oracle) gid=1000(oinstall) groups=1000(oinstall),1200(asmadmin),1201(asmdba),1300(dba),1301(oper)
11gdg-> lsnrctl service

LSNRCTL for Linux: Version 11.2.0.3.0 - Production on 10-JUL-2013 18:28:23

Copyright (c) 1991, 2011, Oracle.  All rights reserved.

Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
Services Summary...
Service "+ASM" has 1 instance(s).
  Instance "+ASM", status READY, has 1 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:0 refused:0 state:ready
         LOCAL SERVER
Service "phydb" has 1 instance(s).
  Instance "phydb", status READY, has 1 handler(s) for this service...
    Handler(s):
      "DEDICATED" established:1347 refused:0 state:ready
         LOCAL SERVER
Service "phydbXDB" has 1 instance(s).
  Instance "phydb", status READY, has 1 handler(s) for this service...
    Handler(s):
      "D000" established:0 refused:0 current:0 max:1022 state:ready
         DISPATCHER <machine: 11gdg.localdomain, pid: 2176>
         (ADDRESS=(PROTOCOL=tcp)(HOST=11gdg.localdomain)(PORT=60468))
The command completed successfully
11gdg-> 

5、将数据库置于read only状态. 

SQL> startup mount;
ORACLE instance started.

Total System Global Area  430075904 bytes
Fixed Size                  2229064 bytes
Variable Size             339741880 bytes
Database Buffers           79691776 bytes
Redo Buffers                8413184 bytes
Database mounted.
SQL> select open_mode from v$database;

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

SQL> alter database open read only;

Database altered.

SQL> select open_mode from v$database;

OPEN_MODE
--------------------
READ ONLY

6、查看数据库当前的scn

SQL> select current_scn from v$database;

CURRENT_SCN
-----------
    4222245

SQL> show user
USER is "SYS"
SQL>