text: -- database creation schema
  DROP DATABASE IF EXISTS company_db;
  
  CREATE DATABASE company_db;
  USE company_db;
  
  CREATE TABLE departments (
    id INTEGER AUTO_INCREMENT PRIMARY KEY,
    department VARCHAR(30)
  );
  
  CREATE TABLE roles (
    id INTEGER AUTO_INCREMENT PRIMARY KEY,
    title VARCHAR(30),
    salary DECIMAL(10,2),
    department_id INTEGER
  );
  
  CREATE TABLE employees (
    id INTEGER AUTO_INCREMENT PRIMARY KEY,
    first_name VARCHAR(30),
    last_name VARCHAR(30),
    role_id INTEGER,
    manager_id INTEGER
  );