ORACLEµÄË÷ÒýºÍÔ¼ÊøÏê½â
* Èç¹ûij¸öÔ¼ÊøÖ»×÷ÓÃÓÚµ¥¶ÀµÄ×ֶΣ¬¼´¿ÉÒÔÔÚ×ֶμ¶¶¨ÒåÔ¼Êø£¬Ò²¿ÉÒÔÔÚ±í¼¶¶¨ÒåÔ¼Êø£¬µ«Èç¹ûij¸öÔ¼Êø×÷ÓÃÓÚ¶à¸ö×ֶΣ¬
±ØÐëÔÚ±í¼¶¶¨ÒåÔ¼Êø
* ÔÚ¶¨ÒåÔ¼ÊøÊ±¿ÉÒÔͨ¹ýCONSTRAINT¹Ø¼ü×ÖÎªÔ¼ÊøÃüÃû£¬Èç¹ûûÓÐÖ¸¶¨£¬ORACLE½«×Ô¶¯ÎªÔ¼Êø½¨Á¢Ä¬ÈϵÄÃû³Æ
¶¨Òåprimary keyÔ¼Êø(µ¥¸ö×ֶΣ©
create table employees (empno number(5) primary key,...)
Ö¸¶¨Ô¼ÊøÃû
create table employees (empno number(5) constraint emp_pk primary key,...)
¶¨Òåprimary keyÔ¼Êø(¶à¸ö×Ö¶Î,ÔÚ±í¼¶¶¨ÒåÔ¼Êø£©
create table employees
(empno number(5),
deptno number(3) not null,
constraint emp_pk primary key(empno,deptno)
using index tablespace indx
storage (initial 64K
next 64K
)
)
ORACLE×Ô¶¯»áΪ¾ßÓÐPRIMARY KEYÔ¼ÊøµÄ×Ö¶Î(Ö÷Âë×Ö¶Î)½¨Á¢Ò»¸öΨһË÷ÒýºÍÒ»¸öNOT NULLÔ¼Êø,¶¨ÒåPRIMARY KEYÔ¼ÊøÊ±¿ÉÒÔΪËüµÄË÷Òý
Ö¸¶¨´æ´¢Î»Öúʹ洢²ÎÊý
alter table employees add primary key (empno)
alter table employees add constraint emp_pk primary key (empno)
alter table employees add constraint emp_pk primary key (empno,deptno)
not nullÔ¼Êø(Ö»ÄÜÔÚ×ֶμ¶¶¨ÒåNOT NULLÔ¼Êø,ÔÚͬһ¸ö±íÖпÉÒÔ¶¨Òå¶à¸öNOT NULLÔ¼Êø)
alter table employees modify deptno not null/null
uniqueÔ¼Êø
create table employees
( empno number(5),
ename varchar2(15),
phone varchar2(15),
email varchar2(30) unique,
deptno number(3) not null,
constraint emp_ename_phone_uk unique (ename,phone)
)
alter table employees
add constraint emp_uk unique(ename,phone)
using index tablespace indx
¶¨ÒåÁËUNIQUEÔ¼ÊøµÄ×Ö¶ÎÖв»Äܰüº¬Öظ´Öµ£¬¿ÉÒÔΪһ¸ö»ò¶à¸ö×ֶζ¨ÒåUNIQUEÔ¼Êø,Òò´Ë£¬UNIQUE¼´¿ÉÒÔÔÚ×ֶμ¶Ò²¿ÉÒÔÔÚ±í¼¶¶¨Ò壬
ÔÚUNIQUEDÔ¼ÊøµÄ×Ö¶ÎÉÏ¿ÉÒÔ°üº¬¿ÕÖµ.
foreign keyÔ¼Êø
* ¶¨ÒåΪFOREIGN KEYÔ¼ÊøµÄ×Ö¶ÎÖÐÖ»Äܰüº¬ÏàÓ¦µÄÆäËü±íÖеÄÒýÓÃÂë×ֶεÄÖµ»òÕßNULLÖµ
* ¿ÉÒÔΪһ¸ö»òÕß¶à¸ö×ֶεÄ×éºÏ¶¨ÒåFOREIGN KEYÔ¼Êø
* ¶¨ÒåÁËFOREIGN KEYÔ¼ÊøµÄÍⲿÂë×ֶκÍÏà
Ïà¹ØÎĵµ£º
oracle±í¿Õ¼ä²Ù×÷Ïê½â
1
2
3×÷Õߣº À´Ô´£º ¸üÐÂÈÕÆÚ£º2006-01-04
5
6
7½¨Á¢±í¿Õ¼ä
8
9CREATE TABLESPACE data01
10DATAFILE '/ora ......
oracle±í¿Õ¼ä²Ù×÷Ïê½â
Ò»¡¢½¨Á¢±í¿Õ¼ä
CREATE TABLESPACE data01
DATAFILE '/oracle/oradata/db/DATA01.dbf' SIZE 500M
UNIFORM SIZE 128k;
¶þ¡¢½¨Á¢UNDO±í¿Õ¼ä
CREATE UNDO TABLESPACE UNDOTBS02
DATAFILE '/oracle/oradata/db/UNDOTBS02.dbf' SIZE 50M
#×¢Ò⣺ÔÚOPEN״̬ÏÂijЩʱ¿ÌÖ»ÄÜÓÃÒ»¸öUNDO±í¿Õ¼ä£¬Èç¹ûÒ ......
(Ò»)ʵÏÖ·ÖÒ³¼°ÐÔÄÜ
OracleµÄ·ÖÒ³²éѯÓï¾ä»ù±¾ÉÏ¿ÉÒÔ°´ÕÕ±¾Îĸø³öµÄ¸ñʽÀ´½øÐÐÌ×Óá£
·ÖÒ³²éѯ¸ñʽ£º
SELECT * from
(
SELECT A.*, ROWNUM RN
from (SELECT * from TABLE_NAME) A
WHERE ROWNUM <= 40
)
WHERE RN >= 21
ÆäÖÐ×îÄÚ²ãµÄ²éѯSELECT * from TABLE_NAME±íʾ²»½øÐзҳµÄÔʼ²éѯÓï¾ä¡£ROWNUM & ......
ËäȻѧϰJavaºÜ¾ÃÁË£¬×Ô¼ºÒ²Á¬½Ó¹ýһЩÊý¾Ý¿â£¬±ÈÈçmysqlÖ®ÀàµÄ£¬Èç½ñÄØ£¬Ò²Ñ§Ï°ÁËÒ»¶Îʱ¼äµÄOracle£¬È»¶øÄØ£¬½ñÌìÊÇÎÒµÚÒ»´ÎÁ¬½ÓOracle£¬ºÙºÙ£¬Ó¦¸Ã»¹²»ËãÌ«³Ù°É¡£
½ñÌìÄØ£¬Óе㱿׾£¬´ó¼ÒĪЦ£¡
ÎÒÕâÊÇÒ»¸ö²éѯÀý×Ó
Ê×ÏÈ£¬Ô ......
¸Õ²ÅÉÏÍøËÑcheckpoint cnt£¬¿´µ½EYGLEдµÄһƪÎÄÕ£¬Ð´µÃ²»´í£¬´æÆðÀ´·½±ãÒÔºóѧϰ¡£
=========================================================================
ͨ¹ýÊÔÑé˵Ã÷checkpoint cnt ºÍcheckpoint scnµÄ¹ØÏµ
1.ÔÚ²»Í¬Ìõ¼þÏÂת´¢¿ØÖÆÎļþ
SQL> alter session set events 'immediate trace name C ......