text: DROP DATABASE IF EXISTS company_DB;
  
  CREATE DATABASE company_DB;
  
  USE company_DB;
  
  CREATE TABLE departments (
    id INT NOT NULL AUTO_INCREMENT,
    name VARCHAR(100) NULL,
    PRIMARY KEY (id)
  );
  
  CREATE TABLE roles (
    id INT NOT NULL AUTO_INCREMENT,
    title VARCHAR(100) NULL,
    salary DECIMAL NULL,
    department_id INT NULL,
    PRIMARY KEY (id)
  );
  
  CREATE TABLE employees (
    id INT NOT NULL AUTO_INCREMENT,
    first_name VARCHAR(100) NULL,
    last_name VARCHAR(100) NULL,
    role_id INT NULL,
    manager_id INT NULL,
    PRIMARY KEY (id)
  );