Oracle碎碎念~2

1. 如何查看表的列名及类型

SQL> select column_name,data_type,data_length from all_tab_columns where owner='SCOTT' and  table_name='EMP';

COLUMN_NAME    DATA_TYPE  DATA_LENGTH
--------------- ---------- -----------
EMPNO        NUMBER            22
ENAME        VARCHAR2        10
JOB        VARCHAR2         9
MGR        NUMBER            22
HIREDATE    DATE             7
SAL        NUMBER            22
COMM        NUMBER            22
DEPTNO        NUMBER            22

8 rows selected.

2. 如何查看表的约束及建立在何列上

SQL> select * from user_cons_columns;

OWNER CONSTRAINT TABLE COLUMN_NAME     POSITION
----- ---------- ----- --------------- ----------
SCOTT FK_DEPTNO  EMP   DEPTNO            1
SCOTT PK_DEPT    DEPT  DEPTNO            1
SCOTT PK_EMP     EMP   EMPNO             1

SQL> select owner,constraint_name,constraint_type,table_name from user_constraints;

OWNER CONSTRAINT C TABLE
----- ---------- - -----
SCOTT FK_DEPTNO  R EMP
SCOTT PK_EMP     P EMP
SCOTT PK_DEPT    P DEPT

3. 如何查看哪个用户对具体目录的操作权限

SQL> select * from dba_tab_privs where table_name='TMP';

GRANT OWN TAB GRA PRIVILEGE                   GRA HIE
----- --- --- --- ------------------------    --- ---
SCOTT SYS TMP SYS WRITE                       NO  NO
SCOTT SYS TMP SYS READ                        NO  NO

4. 如何查看用户拥有的对象权限和系统权限

SQL> select * from user_tab_privs;

GRANT OWN TAB GRA PRIVILEGE                   GRA HIE
----- --- --- --- -------------------------   --- ---
SCOTT SYS TMP SYS WRITE                       NO  NO
SCOTT SYS TMP SYS READ                        NO  NO

SQL> select * from user_sys_privs;

USERNAME                       PRIVILEGE                 ADM
------------------------------ ------------------------  ---
SCOTT                          UNLIMITED TABLESPACE      NO

5. 如何判断数据库启动用的是pfile还是spfile

SQL> show parameter spfile

若有值，则是用spfile启动，若为空，则是用pfile启动

6. When SQL*Plus starts, and after CONNECT commands, the site profile (e.g. $ORACLE_HOME/sqlplus/admin/glogin.sql) and the user profile (e.g. login.sql in the working directory) are run. The files may contain SQL*Plus commands.

这两个文件可以自定义SQL*Plus命令

7. sqlplus -L 

-L代表Attempts to log on just once, instead of reprompting on error.即只判断一次用户名和密码是否匹配，倘若不匹配，则立即退出，如果不加L，则有三次尝试机会

[oracle@node3 ~]$ sqlplus -L scott/
SQL*Plus: Release 11.2.0.1. Production on Thu Dec  ::
Copyright (c) , , Oracle.  All rights reserved.
ERROR:
ORA-: invalid username/password; logon denied
SP2-: Unable to connect to Oracle.  Exiting SQL*Plus

8. 密码文件

密码文件的默认位置为:$ORACLE_HOME/dbs

密码文件的查找顺序：orapw<sid> -->  orapw  --> Failure

所以在创建密码文件时filename只能为orapw<sid>或者orapw

9. 查看谁被授予了SYSDBA或者SYSOPER权限

SQL> select * from v$pwfile_users;

10. 查看数据字典中有关权限的表

SQL> select * from dict where table_name like '%PRIVS%';

11. 批量插入

insert all
          into test1
          into test2
      select * from dba_objects;

12. beq

在sqlplus中输入conn / as sysdba,这时候由sqlplus启动一个服务器进程，通过ps命令查看到这这个服务器进程的protocol=beq 而不是TCP，beq是bequeath protocol的简称，是一个sql*net protocol有点类似于IPC,仅仅是作为本地连接才能使，即客户机和服务器程序在同一个服务器上。beq可以在不需要listener的情况一下，建立一个专用连接。 

如下所示：

oracle    1777  1776  0 18:04 ?        00:00:00 oracleorcl (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq)))

如果是走网络连接，则显示如下：

oracle    1791     1  2 18:05 ?        00:00:00 oracleorcl (LOCAL=NO)

13. Oracle 11g下的ipcs -m

在11g下，通过ipcs -m观察的结果如下：

[root@node2 oracle]# ipcs -m

------ Shared Memory Segments --------
key        shmid     owner     perms       bytes      nattch     status
0x00000000      oracle
0x00000000      oracle
0x00000000      oracle
0x00000000     oracle
0xefc07fc8     oracle                          

bytes列均为4096,而在10g下，owner列只有一个oracle用户，且bytes是一个具体的数值。为什么11g下的bytes为4096且nattch为0，具体原因可参考：http://www.oracledatabase12g.com/archives/11g%E5%86%85%E5%AD%98%E7%AE%A1%E7%90%86%E6%96%B0%E7%89%B9%E6%80%A7%E7%9A%84internal%E8%A1%A8%E7%8E%B0.html

14. 如何查看当前会话的SID

SQL> select sid from v$mystat where rownum=1;

15. 如何查看连接到当前数据库的会话

SQL> select sid,username,status from v$session;

16. 如何kill掉会话

SQL> select sid,serial# from v$session where username='SCOTT';

       SID    SERIAL#
---------- ----------
       19      109

SQL> alter system kill session '19,109';

System altered.
SQL> select sid,serial#,status from v$session where username='SCOTT';

       SID    SERIAL# STATUS
---------- ---------- --------
        19      109   KILLED

关于kill会话，可参考 http://www.cnblogs.com/kerrycode/p/4034231.html

17. 如何查看oracle用户密码

SQL> select name,password from sys.user$;

18. 不知道某个用户的密码，又想用这个用户做一些操作，又不能去修改掉这个用户的密码

以test用户为例，原来test用户的密码为test

SQL> conn test/test
Connected.
SQL> conn /as sysdba
Connected.
SQL> select name,password from sys.user$ where name='TEST';

NAME                           PASSWORD
------------------------------ ------------------------------
TEST                           7A0F2B316C212D67

1 row selected.

SQL> alter user test identified by hello;

User altered.

SQL> conn test/hello
Connected.
SQL> select * from tab;

TNAME                          TABTYPE  CLUSTERID
------------------------------ ------- ----------
CHAINED_ROWS                   TABLE
EMPLOYEES                      TABLE
EMPLOYEES_TMP                  TABLE

3 rows selected.

SQL> conn /as sysdba
Connected.
SQL> alter user test identified by values '7A0F2B316C212D67';

User altered.

SQL> conn test/test
Connected.

19. 如何查看数据库属性

SQL> select property_name,property_value from database_properties;

20. 如何查看特定分区的值

SQL> select count(*) from test partition(p1);

21. 查看tablespace的数据文件

SQL> select tablespace_name,file_name from dba_data_files;

22. 查看用户被赋予的角色

SQL> select * from dba_role_privs where grantee='SCOTT';

23. 在PL/SQL Developer中如何查看表结构

CTRL+表名

24. 如何原样输出字符串

SQL> select  q'([@#$%^&*~?/" '])' from dual;

Q'([@#$%^&*~?/"
---------------
[@#$%^&*~?/" ']

SQL> select  q'2I'm Victor2' from dual;

Q'2I'MVICT
----------
I'm Victor

注意：  1> Q'后跟起始分隔符，起始分隔符后的字符串原样输出，起始分隔符必须有配对的结束分隔符。

2> 分隔符可以为数字、字母、特殊字符。但'&'不能作为分隔符，因为'&'意思是传入参数。

3> '['、'('、'{'作为分隔符，必须以']'、')'、'}'结束。

25. TWO_TASK  

TWO_TASK lets you silently support a tns network connect string, that is, instead of: sqlplus scott/tiger@tnsname
you can: export TWO_TASK=tnsname
sqlplus scott/tiger <<<== that has an implied @tnsname
oracle_sid is used for a local connection - direct to the server - without using a listener 

the environment variable name is LOCAL on windows NT. set LOCAL=service_name

TWO_TASK是环境变量，通过将其设置为网络字符串，用户通过网络登录时，可不用指定网络字符串，譬如，sqlplus scott/tiger@orcl,通过将TWO_TASK设置为orcl，用sqlplus scott/tiger可直接登录。

注意：Linux和Windows下的设置方式不同，Linux下为export TWO_TASK=orcl，Windows下为set LOCAL=orcl

26. wmsys.wm_concat

该函数可以把列值以","号分隔起来,并显示成一行

SQL>  select wmsys.wm_concat(dname) from dept;

WMSYS.WM_CONCAT(DNAME)
--------------------------------------------------------------------------------
ACCOUNTING,RESEARCH,SALES,OPERATIONS,IT

--将逗号替换为'|'号
SQL>  select replace(wmsys.wm_concat(dname),',','|') from dept;

REPLACE(WMSYS.WM_CONCAT(DNAME),',','|')
--------------------------------------------------------------------------------
ACCOUNTING|RESEARCH|SALES|OPERATIONS|IT

27. 如何将一行的值转换为列

原始输出如下：

SQL> select * from dept where deptno=10;

    DEPTNO DNAME          LOC
---------- -------------- -------------
        10 ACCOUNTING     NEW YORK

那么如何将这一行的值转换为列呢？

SQL> with t as
  2    ( select deptno,dname,loc from dept where deptno=10)
  3  select to_char(deptno) from t
  4  union all
  5  select dname from t
  6  union all
  7  select loc from t;

TO_CHAR(DEPTNO)
----------------------------------------
10
ACCOUNTING
NEW YORK

28. dual

SQL> create table dual as (select * from dual union all select * from dual);

Table created.

SQL> select * from dual;

D
-
X
X

SQL> select sysdate from dual;

SYSDATE
---------
10-JUN-15
10-JUN-15

29. 生成AWR报告的三个条件，以test用户为例

grant create session to test;
      grant select any dictionary to test;
      grant execute on dbms_workload_repository to test;

30. 单引号对应的是chr(39)

39其实是单引号的ASCII码

31. 如何查找堵塞会话并杀掉它

SQL> select sid,serial#,blocking_session from v$session where username='SCOTT'; 

       SID    SERIAL# BLOCKING_SESSION
---------- ---------- ----------------
       125          7              142

SQL> select sid,serial#,username from V$session where sid=142;

       SID    SERIAL# USERNAME
---------- ---------- ------------------------------
       142         27 SYS

SQL> alter system kill session '142,27';

System altered.

32. 如何设置sqlprompt

首先利用define命令显示预定义的SQL*Plus变量列表

SQL>define
DEFINE _DATE           = "16-JUL-15" (CHAR)
DEFINE _CONNECT_IDENTIFIER = "test" (CHAR)
DEFINE _USER           = "SCOTT" (CHAR)
DEFINE _PRIVILEGE      = "" (CHAR)
DEFINE _SQLPLUS_RELEASE = "1102000400" (CHAR)
DEFINE _EDITOR           = "vim" (CHAR)
DEFINE _O_VERSION      = "Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options" (CHAR)
DEFINE _O_RELEASE      = "1102000400" (CHAR)

设置sqlprompt

SQL>set sqlprompt &_USER@&_CONNECT_IDENTIFIER>
SCOTT@test>

33. 如何查看后台进程的作用

SQL> select name,description from v$bgprocess;

34. 如何查看Oracle的版本号

SQL> select * from v$version;

35. Database Sample Schemas

http://docs.oracle.com/cd/E11882_01/server.112/e10831/toc.htm

36. 如何找出给定数之间的最大值和最小值   

SQL> select least(1,2,3) from dual;

LEAST(1,2,3)
------------
           1

SQL> SELECT greatest (1,2,3) from dual ;

GREATEST(1,2,3)
---------------
              3

37. 用shell脚本获取用户连接数

刚开始是这样：

#!/usr/bin/sh
export ORACLE_HOME=/opt/app/oracle/product/11.2./
export TNS_ADMIN=/home/monitor
sqlplus='/opt/app/oracle/product/11.2.0/bin/sqlplus'
output=`$sqlplus -s test/test@orcl << EOF
set feedback off;
set heading off;
select count(*) from v$session where status='ACTIVE';
EOF`
echo $output

但是执行的时候会报如下错误：

select count(*) from v where status='ACTIVE'
ERROR at line : ORA-: procedure, function, package, or type is not allowed here

原因在于$session当做变量了，当然为空了。

根据网上的方案，$前面加个转义符，即v$session修改为v\$session，但还是没有效果。

解决方法，在前面定义了一个session变量

#!/usr/bin/sh
export ORACLE_HOME=/opt/app/oracle/product/11.2./
export TNS_ADMIN=/home/monitor
session='$session'
sqlplus='/opt/app/oracle/product/11.2.0/bin/sqlplus'
output=`$sqlplus -s audit_vces/audit_vces@orcl << EOF
set feedback off;
set heading off;
select count(*) from v$session where status='ACTIVE';
EOF`
echo $output