如何以一种员工只能属于一个部门的方式创建数据库模式？

Question

How to create database schema in such a way that one employee can be part of one department only. There are three tables of a company "Employee table" "Department table" and "Region table".

Answer 1

You do this by having a department_id column in employees :

create table employees (
    . . . ,
    department_id int,
    . . . 
    constraint fk_employees_department foreign key (department_id) references departments(department_id)
);

If you want to require that each employee is always in a department, then use not null :

department_id int not null,