System localization - Dameng database basic operation commands

1. Query the database version

select * from v$version;

2. View authorization information

select * from  v$license;

3. View Dameng database name

select name,create_time from v$database;

4. Check whether the case configuration is sensitive

--Size sensitive (1 is case sensitive, 0 is case insensitive)

SELECT SF_GET_CASE_SENSITIVE_FLAG();
或
SELECT CASE_SENSITIVE()

5. Query the maximum connection of the database

select SF_GET_PARA_VALUE(2,'MAX_SESSIONS');

6. Check the current status of Dameng database

select status$ from v$instance;

7. Check the authorization expiration date

select EXPIRED_DATE  from v$license;

8. Query the location of data files

select GROUP_ID , ID ,path,STATUS$ from v$datafile;

9. Query table space size

select FILE_NAME,FILE_ID,TABLESPACE_NAME,BYTES/1024/1024||'M'  from dba_data_files;

10. Query table space usage

select t1.NAME tablespace_name,
t2.FREE_SIZE*SF_GET_PAGE_SIZE()/1024/1024 ||'M' free_space,
t2.TOTAL_SIZE*SF_GET_PAGE_SIZE()/1024/1024 ||'M' total_space,
t2.FREE_SIZE*100/t2.total_size "% FREE" 
from V$TABLESPACE t1, V$DATAFILE t2 
where t1.ID=t2.GROUP_ID;

11. Query all SCHEMA

 select * from dba_objects where object_type='SCH';

12. Query all users

select username from dba_users;

13. Switch SCHEMA

set schema "testSchema";

14. Create SCHEMA

CREATE SCHEMA "testSchema";

15. Full table name in query mode

select TABLE_NAME from all_tables WHERE OWNER='testSchema';

16. Delete SCHEMA

drop schema "testSchema";

17. Column comments

COMMENT ON COLUMN testSchema.peoples.role_id is '角色Id';

18. Query column comments

select * from SYSCOLUMNCOMMENTS 
where SCHNAME='testSchema' and TVNAME='peoples' and COLNAME='role_id';

19. Table comments

comment on table testSchema.peoples is '这是一个表注释';

20. Query table comments

select * from SYSTABLECOMMENTS where SCHNAME='testSchema' and TVNAME='peoples';

21. Create table space

CREATE TABLESPACE MANAGEMENT DATAFILE 'MANAGEMENT.DBF' SIZE 128;

22. View table space

select * from dba_data_files;
select * from dba_tablespaces;
select * from v$tablespace;

23. Create user

CREATE USER testUser IDENTIFIED BY "testUsersPwd" DEFAULT TABLESPACE MANAGEMENT;
GRANT DBA TO testSchema;

24. Check the number of connections of the current instance

select clnt_ip,user_name,state,count(*) from v$sessions group by clnt_ip,user_name,state;