启动状态
SQL语句
结果
nomount
select status from v$instance;
STARTED
select open_mode from v$database;
ERROR at line 1:
ORA-01507: database not mounted
mount
select status from v$instance;
MOUNTED
select open_mode from v$database;
MOUNTED
open
select status from v$instance;
OPEN
select open_mode from v$database;
READ WRITE 或者 READ ONLY


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
Alert 日志
11g以前oracle的alter文件是在bdump目录下呢。 oracle 11g一改常态以XML与传统的文本两种格式提供 Alert 日志。 oracle 11g新的日志的位置由Automatic Diagnostic Respository(ADR)决定。 可以通过新的初始化参数DIAGNOSTIC_DEST控制ADR BASE的位置。 
显示DIAGNOSTIC_DEST的位置
SQL> show parameter DIAGNOSTIC_DEST;

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
diagnostic_dest string /u01/app/oracle
查询两种日志的位置 查询xml文件的目录
SQL> select value from v$diag_info where name='Diag Alert';

VALUE
--------------------------------------------------------------------------------
/u01/app/oracle/diag/rdbms/test/test/alert
查询文本文件的目录 
SQL> select value from v$diag_info where name='Diag Trace';

VALUE
--------------------------------------------------------------------------------
/u01/app/oracle/diag/rdbms/test/test/trace
也可以通过查询background_dump_dest来查看oracle的文本日志
SQL> show parameter background_dump_dest;
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
background_dump_dest string /u01/app/oracle/diag/rdbms/tes
                                                 t/test/trace

OR

SQL> select value from v$parameter where name='background_dump_dest';
VALUE
--------------------------------------------------------------------------------
/u01/app/oracle/diag/rdbms/test/test/trace