操作數據表
阿新 • • 發佈:2019-05-16
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1.對數據表:
create table
alter table add|drop
drop table
2.對表中數據:
insert into values
update set
delete
3.對約束(constraint)
例:
(1)not null:
alter table table1
alter column column1 int null
alter table table1
(2)primary key創建主鍵約束:
add constraint constraint1 primary key(column1)
(3)unique創建唯一約束
add constraint constraint1 unique(column1)
(4)check創建檢查約束
add constraint constraint1 check(express)
(5)default默認約束
add constraint constraint1 default ‘男’ for sex
(6)foreign key 外鍵約束
add constraint constraint1 foreign key(column1)reference table2(column1)
刪除 primary key/unique/check/default/foreign key 約束:
drop constraint constraint1
/*
constraint1 約束名
column1 字段名
table1 table2 表名
*/
操作數據表