create database test
GO
use test

create table departments  (
	dept_id int identity(1,1)  NOT NULL,
	name varchar(30) not null
)

create table employees  (
	empl_id int identity(1,1)  NOT NULL,
	name varchar(30) not null,
	dept_id int	
)

alter table employees
add constraint pk_employees primary key clustered ( empl_id )

alter table departments
add constraint pk_departments primary key clustered ( dept_id )


alter table employees
add constraint fk_employees_departments foreign key ( dept_id )
references departments ( dept_id )

insert into departments (name) values ('Sales');
insert into departments (name) values ('Games');
insert into departments (name) values ('HR');
insert into departments (name) values ('Finance');
insert into departments (name) values ('Systems');

insert into employees (name, dept_id) values ('Jackson',1);
insert into employees (name, dept_id) values ('Smith',2);
insert into employees (name, dept_id) values ('Gates',2);
insert into employees (name, dept_id) values ('McDonald',3);
insert into employees (name, dept_id) values ('Ohara',5);
insert into employees (name, dept_id) values ('Toureg',null);