text: drop database if exists hr_tracker;
  create database hr_tracker;
  
  use hr_tracker;
  
  create table department(
      id int not null auto_increment primary key,
      name varchar(30)
  );
  
  create table role(
      id int not null auto_increment primary key,
      title varchar(30),
      salary decimal(20,2),
      department_id int
  );
  
  create table employee(
      id int not null auto_increment primary key,
      first_name varchar(30),
      last_name varchar(30),
      role_id int,
      manager_id int
  )
  ;