SQL Server中用SQL命令建表和主外键约束

create table dept
(
	dept_name nvarchar(20) not null,    
	dept_address nchar(20),
	dept_id int constraint PK_dept primary key     --dept表的主键，命名为PK_dept
)

create table emp
(
	emp_name nvarchar(20) not null,
	emp_sex nchar(1),
	emp_age int,
	emp_id int constraint PK_emp primary key,     --emp表的主键
	dept_id int constraint FK_emp_dept foreign key references dept(dept_id)   --外键
)

create table student
(
	stu_id int constraint PK_stu primary key,
	stu_name nvarchar(20) unique not null,                --unique约束，stu_name的值不能重复
	stu_sex nvarchar(1) not null default(‘男‘),           --stu_sex的默认值为：男
	stu_sal int check (stu_sal>=1000 and stu_sal<=8000)   --check约束，stu_sal的值只能在1000到8000之间
)


insert into student(stu_id,stu_name,stu_sal) values(1,‘张三‘,6000);    --没有给stu_sex赋值，默认为男
insert into student values(2,‘李四‘,‘男‘,7000);
insert into student values(3,‘小娟‘,‘女‘,5000);