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