SQL2012_主键约束

SQL中主键的约束

if exists(select * from sys.databases where name='SchDB')

drop database SchDB

create database SchDB on primary(

name='S_DB',filename='D:\S_DB.mdf',size=5mb,maxsize=100mb,filegrowth=10%

),( name='S_DB_N_1',filename='D:\S_DB_N_1.ndf',size=1mb,maxsize=50mb,filegrowth=1mb)

,( name='S_DB_N_2',filename='D:\S_DB_N_2.ndf',size=1mb,maxsize=50mb,filegrowth=1mb)

,filegroup XXX( name='S_DB_N_3',filename='D:\S_DB_N_3.ndf',size=1mb,maxsize=50mb,filegrowth=1mb)

,( name='S_DB_N_4',filename='D:\S_DB_N_4.ndf',size=1mb,maxsize=50mb,filegrowth=1mb)

,( name='S_DB_N_5',filename='D:\S_DB_N_5.ndf',size=1mb,maxsize=50mb,filegrowth=1mb)

go

alter database SchDB add filegroup YYY

go

alter database SchDb add file(

name='S_DB_N_6',filename='D:\S_DB_N_6.ndf',

size=1mb,maxsize=50mb,filegrowth=1mb

)to filegroup YYY

alter database SchDB modify filegroup YYY default

use SchDB

create table U3(

id int constraint PK_HAHA primary key,

age int constraint CK_HAHA check(age in(20,70,80)) default 80

)

insert into U3 output inserted.* values(default)

insert into U3 output inserted.* values(30)

sp_renameDB 'SchDB','HEIHEI'

create schema XIXI

create table XIXI.U(

id int foreign key(id) references U3(id)

)

create table Y(

id int ,

s_id int

constraint PK_id_s_id primary key(id,S_id)

)

--创建唯一约束

create table K1(name nvarchar(20) unique)

create table K3(

id int not null,--如果是主键必须添加not null

name nvarchar(20) constraint UQ_Name2 unique

)

--修改表创建约束

alter table K3 add constraint PK_id primary key(id)

create table a(--主表

aid int primary key

)

create table b(--从表

bid int foreign key(bid) references a(aid)

)

drop table b

drop table a