text: DROP DATABASE IF EXISTS company_db;
  
  CREATE DATABASE company_db;
  
  USE company_db;
  
  create table department (
      id varchar(10) unique not null,
      name varchar(30) not null,
      primary key (id)
  );
  
  create table role (
      id int auto_increment not null,
      title varchar(50) not null,
      salary decimal (10,2) not null,
      department_id varchar(10) not null,
      primary key (id)
  );
  
  create table employee (
      id int AUTO_INCREMENT not null,
      first_name varchar(30) not null,
      last_name varchar(30) not null,
      role_id int not null,
      manager_id int null,
      primary key (id)
  );