oracle 常用性能查询SQL分享
select count(1) from dictionary;
select * from dba_data_files;
select count(1) from dba_objects t where t.owner='BESTTONE';
select * from dba_tablespaces t where t.tablespace_name='BESTTONE';
select count(1) from dba_tables t where t.owner='BESTTONE';
select t.table_name,t.comments from dictionary t where t.table_name like 'V$%';
select * from dba_constraints;
select * from dba_cons_columns;
select * from dba_tablespaces t where t.tablespace_name='SIM002';
CREATE TABLESPACE SS DATAFILE 'D:\ORACLE\ORADATA\BSTO\SS.DBF' SIZE 1M;
SELECT T.tablespace_name, T.status from DBA_TABLESPACES T;
SELECT T.TABLESPACE_NAME,T.FILE_NAME from DBA_DATA_FILES T;
ALTER TABLESPACE SIM002 OFFLINE;
ALTER TABLESPACE SIM002 ONLINE;
SELECT T.os_username,
T.username,
T.terminal,
DECODE(T.returncode,
'0',
'Connected',
'1005',
'failedNull',
'1017',
'failed'),
to_char(t.timestamp, 'dd-mon-yy hh24:mi:ss'),
to_char(t.logoff_time, 'dd-mon-yy hh24:mi:ss')
from DBA_AUDIT_SESSION T;--尝试登陆审计
select t.action,t.name from audit_actions t;
select * from dba_audit_object;
select * from v$sesstat;
select a.sid,a.value "total cpu time" from v$sesstat a ,v$statname b
where a.STATISTIC#=b.STATISTIC# and b.NAME='cpu used by this session'
order by a.sid;--会话级服务时间值
select sum(time_waited) &quo
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什么是合并多行字符串(连接字符串)呢,例如:
SQL> desc test;
Name Type Nullable Default Comments
------- ------------ -------- ------- --------
COUNTRY VARCHAR2(20) Y &nb ......
||------- 维护数据完整性 -------||
【约束】
//约束
not null //非空
unique //唯一 不能重复,但可以为空
primary key //主键
foreign key //外键
check //满足条件
//商店售货系统表设计案例(1)
//goods 商品表
goodsid ......
1、查看当前数据库的状态
SELECT
DATABASEPROPERTY
('pubs'
,'IsFulltextEnabled'
)
2、打开FullText功能
sp_fulltext_databse
'enable'
关闭此功能
& ......
--> --> (Roy)生成测试数据
if not object_id('Class') is null
drop table Class
Go
Create table Class([Student] nvarchar(2),[Course] nvarchar(2),[Score] int)
Insert Class
select N'张三',N'语文',78 union all
select N'张三',N'数学',87 union all
select N'张三',N'英语',82 union all
sel ......
用sql*plus或第三方可以运行sql语句的程序登录数据库:
增加一个列:
ALTER TABLE 表名 ADD(列名 数据类型);
如:
ALTER TABLE emp ADD(weight NUMBER(38,0));
修改一个列的数据类型(一般限于修改长度,修改为一个不同类型时有诸多限制):
ALTER TABLE 表名 MODIFY(列名 数据类型);
如:
ALTER TABLE emp MODIFY(wei ......