Oracle 數(shù)據(jù)完整性的維護(hù)

1.刪除約束  
alter table table_name drop constraint constraint_name;  
2.創(chuàng)建主鍵  
alter table table_name add constraint constraint_name primary key(column_name1,column_name2);   -
 

3.創(chuàng)建唯一約束  
alter table table_name add constraint constraint_name unique(column_name1,column_name2);  
4.創(chuàng)建外鍵約束  
alter table table_name1 add constraint constraint_name foreign key(column_name1) references table_name2(column_name1);  
enable/disable：約束/不約束新數(shù)據(jù)  
novalidate/validate:不對/對老數(shù)據(jù)進(jìn)行驗(yàn)證  
alter table table_name add constraint constraint_name check(column_name like 'B%') enable/disable novalidate/validate;  
5.修改約束條件，延時(shí)驗(yàn)證，commit時(shí)驗(yàn)證  
alter table table_name modify constraint constraint_name initially deferred;  
6.修改約束條件，立即驗(yàn)證  
alter table table_name modify constraint constraint_name initially immediate;  
7.設(shè)置約束延遲/立即驗(yàn)證  
alter session set constraints=deferred/immediate;  
8.刪除表時(shí)刪除約束  
drop一個(gè)有外鍵的主鍵表,帶cascade constraints參數(shù)級聯(lián)刪除  
drop table table_name cascade constraints;  
9.當(dāng)truncate外鍵表時(shí)，先將外鍵設(shè)為無效，再truncate;  
truncate table table_name;  
設(shè)約束條件無效  
alter table table_name disable constraint constraint_name;  
alter table table_name enable novalidate constraint constraint_name
 

服務(wù)器租用/服務(wù)器托管中國五強(qiáng)！虛擬主機(jī)域名注冊頂級提供商！15年品質(zhì)保障！--億恩科技[ENKJ.COM]