sql2005数据完整性之约束和规则

--数据的完整性

六种约束：not null 、check、unique、primary key、foreign key、default

--创建唯一约束

--这是删除唯一约束

alter table xibu

drop constraint weiyi

--这是建立唯一约束

alter table xibu

add constraint weiyi

unique nonclustered (xbName)

alter table xibu

alter column asd char(8)

--这是check约束

insert xs values('010101000017','克群','ａ','1989-2-9','2010-9-1','0101011','04','0402')

select * from xs

if exists(ck_xs)

alter table xs

drop constraint CK_xs

alter table xs

add constraint aaa

check(sex = '男')

--withnocheck对你以前插入的数据不进行检查
alter table xs with nocheck add

constraint CK_sex check(sex ='男' or sex='女')

exec sp_help xs--这是查看表结构

--这是default约束

alter table bj drop constraint DF_bj_bz

alter table bj add constraint DF_bj_bz default '我爱你' for bz;

create table test

(

id int not null primary key,

name varchar(10) not null

)

drop table test

alter table test

drop constraint aaa

alter table test with nocheck

add constraint aaa default '我真的' for name

exec sp_help test

insert into test values(2,default);

select * from test

规则
/*数据的完整性*/

--规则的创建　

create rule check_rule

as

@a = '男' or @a = '女'

--将规则绑定到数据库表的字段上

exec sp_bindrule 'check_rule', 'test.name'

insert into test values(1, '男');

select * from test

--注意：规则可以用到多个表上

select * into new_table from test

select * from new_table

exec sp_bindrule 'check_rule', 'new_table.name'

insert into new_table values(1, 'asd');

--删除绑定到表中某个字段上的规则

exec sp_unbindrule 'new_table.name'

exec sp_unbindrule 'test.name'

--删除规则

drop rule check_rule

--default规则的一些应用

--创建默认值

create default ch_default

as '曹欢'

--将默认值绑定到数据库表的某个字段

exec sp_bindefault ch_default,'test.name'

insert into test values(13,default);

select * from test

--删除绑定到表字段上的default约束

exec sp_unbindefault 'test.name'

--删除default的默认值

drop default ch_default

--这是对这节的练习

create table test1 (

id int identity(1,1) primary key ,

sex varchar(4) not null,

name varchar(12)

)

select * from test1

exec sp_help test1

--创建规则

create rule check_rule

as

@sex = '男' or @sex = '女'

--把规则应运到

exec sp_bindrule 'check_rule','test1.sex'

exec sp_unbindrule 'test1.sex'

drop rule check_rule

insert into test1 values('男','asd')

select * from test1

create default default_rule

as '曹欢'

exec sp_bindefault 'default_rule','test1.name'

exec sp_unbindefault 'test1.name'

drop default default_rule

insert into test1 values('男',default)

select * from test1