text: drop database if exists emp_trackerDB;
  create database emp_trackerDB;
  use emp_trackerDB;
  create table department (
    id int not null auto_increment,
    name varchar(30),
    primary key (id)
  );
  create table role (
    id int auto_increment not null,
    title varchar(30),
    salary decimal,
    department_id int,
    primary key (id),
    foreign key (department_id) references role(id)
  );
  create table employees (
    id int auto_increment not null,
    first_name varchar(30),
    last_name varchar(30),
    role_id int,
    manager_id int,
    primary key (id),
    foreign key (role_id) references role(id),
    foreign key (manager_id) references role(id)
  );
  select
    *
  from
    department;
  select
    *
  from
    role;
  select
    *
  from
    employee;