ORACLE经常使用系统查询

1
查询系统全部对象

SELECT OWNER,
OBJECT_NAME, OBJECT_TYPE,
CREATED, LAST_DDL_TIME,
TIMESTAMP,
STATUS

FROM DBA_OBJECTS
WHERE OWNER=UPPER('SCOTT')

2
查看系统全部表

SELECT OWNER,
TABLE_NAME, TABLESPACE_NAME
FROM DBA_TABLES

3
查看全部用户的表

SELECT
OWNER, TABLE_NAME,
TABLESPACE_NAME FROM ALL_TABLES

4
查看当前用户表

SELECT
TABLE_NAME, TABLESPACE_NAME
FROM USER_TABLES

5
查看用户表索引

SELECT T.*,I.INDEX_TYPE
FROM USER_IND_COLUMNS T,
USER_INDEXES I WHERE

T.INDEX_NAME=
I.INDEX_NAME AND T.TABLE_NAME
= I.TABLE_NAME

AND
T.TABLE_NAME =
'要查询的表'

6
查看主键

SELECT CU.*
FROM USER_CONS_COLUMNSCU,
USER_CONSTRAINTS AU

WHERE CU.CONSTRAINT_NAME
= AU.CONSTRAINT_NAME

AND AU.CONSTRAINT_TYPE
=
UPPER('P')
AND AU.TABLE_NAME
=
'要查询的表'

7
查看唯一性约束

SELECT COLUMN_NAME
FROM USER_CONS_COLUMNSCU,
USER_CONSTRAINTS AU

WHERE CU.CONSTRAINT_NAME
= AU.CONSTRAINT_NAME
AND AU.CONSTRAINT_TYPE
=
UPPER('U')

AND AU.TABLE_NAME
=
'要查询的表'

8
查看外键

SELECT
*
FROM USER_CONSTRAINTS C
WHERE C.CONSTRAINT_TYPE
=
'R'
AND C.TABLE_NAME
=
'要查询的表'

SELECT
*
FROM USER_CONS_COLUMNSCL
WHERE CL.CONSTRAINT_NAME
=
'外键名称'

SELECT
*
FROM USER_CONS_COLUMNSCL
WHERE CL.CONSTRAINT_NAME
=
'外键引用表的键名'

9
查看表的列属性

SELECT T.*,C.COMMENTS
FROM USER_TAB_COLUMNS T,
USER_COL_COMMENTS C

WHERE T.TABLE_NAME
= C.TABLE_NAME
AND T.COLUMN_NAME
= C.COLUMN_NAME
AND T.TABLE_NAME
=
'要查询的表'

10 查看全部表空间

SELECT TABLESPACE_NAME
FROM DBA_DATA_FILES
GROUP
BY TABLESPACE_NAME

11 查看oracle最大连接数

SQL>SHOW PARAMETER PROCESSES

NAME
TYPE VALUE

----------------------------------------------- ------------------------------

aq_tm_processes
integer 0

db_writer_processes
integer 1

gcs_server_processes
integer 0

global_txn_processes
integer 1

job_queue_processes
integer 1000

log_archive_max_processes
integer 4

processes
integer 150

12 改动最大连接数

SQL>ALTER SYSTEM SET PROCESSES=VALUE SCOPE=SPFILE

–重新启动数据库

SQL>SHUTDOWN ABORT

SQL>START FORCE

13 查看当前连接数

SQL>SELECT * FROM V$SESSION WHERE USERNAME IS NOT NULL;

14 查看不同用户的连接数

SQL>SELECT USERNAME,COUNT(USERNAME) FROM V$SESSION WHERE USERNAME IS NOT NULL GROUPBY USERNAME;

#查看指定用户的连接数

15 查看活动的连接数

SQL>SELECT COUNT(*) FROM V$SESSION WHERE STATUS='ACTIVE';

#查看并发连接数

16 查看指定程序的连接数

SQL>SELECT COUNT(*) FROM V$SESSION WHERE PROGRAM='JDBC THIN CLIENT';

#查看jdbc连接oracle的数目

17 查看数据库安装实例(dba权限)

SQL>SELECT * FROM V$INSTANCE;

18 查看执行实例名

SQL>SHOW PARAMETER INSTANCE_NAME;

19 查看数据库名

SQL>SHOW PARAMETER DB_NAME;

20 查看数据库域名

SQL>SHOW PARAMETER DB_DOMAIN;

21 查看数据库服务名

SQL>SHOW PARAMETER SERVICE_NAMES;

22 查看全局数据库名

SQL>SHOW PARAMETER GLOBAL;

23 查看表空间使用率

SELECT DBF.TABLESPACE_NAME,

DBF.TOTALSPACE "总量(M)",

DBF.TOTALBLOCKS AS "总块数",

DFS.FREESPACE "剩余总量(M)",

DFS.FREEBLOCKS "剩余块数",

(DFS.FREESPACE
/ DBF.TOTALSPACE)
*
100
AS "空暇比例"

FROM
(SELECT
T.TABLESPACE_NAME,

SUM(T.BYTES)
/
1024
/
1024 TOTALSPACE,

SUM(T.BLOCKS)
TOTALBLOCKS

FROM DBA_DATA_FILES T

GROUP
BY T.TABLESPACE_NAME)
DBF,

(SELECT
TT.TABLESPACE_NAME,

SUM(TT.BYTES)
/
1024
/
1024 FREESPACE,

SUM(TT.BLOCKS)
FREEBLOCKS

FROM DBA_FREE_SPACE TT

GROUP
BY TT.TABLESPACE_NAME)
DFS

WHERE
TRIM(DBF.TABLESPACE_NAME)
=
TRIM(DFS.TABLESPACE_NAME)

SELECT T.NAME"TABLESPACE NAME",

FREE_SPACE,

(TOTAL_SPACE
- FREE_SPACE)
USED_SPACE,

TOTAL_SPACE

FROM
(SELECT
TABLESPACE_NAME,
SUM(BYTES
/
1024
/
1024)
FREE_SPACE

FROM SYS.DBA_FREE_SPACE

GROUP
BY TABLESPACE_NAME)
FREE,

(SELECT
B.NAME,
SUM(BYTES
/
1024
/
1024)
TOTAL_SPACE

FROM SYS.V_$DATAFILE A,
SYS.V_$TABLESPACE B

WHERE A.TS#
= B.TS#

GROUP
BY B.NAME)
T

WHERE
FREE.TABLESPACE_NAME = T.NAME