text: 
  DROP DATABASE IF EXISTS company_DB;
  
  CREATE DATABASE company_DB;
  
  USE company_DB;
  
  CREATE TABLE department (
    id INT NOT NULL AUTO_INCREMENT,
    name VARCHAR(30) NOT NULL,
    PRIMARY KEY (id)
  );
  
  CREATE TABLE role (
    id INT NOT NULL AUTO_INCREMENT,
    title VARCHAR(30) NOT NULL,
    salary DECIMAL(10,2) NOT NULL,
    department_id INT NOT NULL,
    PRIMARY KEY (id)
  );
  
  CREATE TABLE employee (
    id INT NOT NULL AUTO_INCREMENT,
    first_name VARCHAR(75) NOT NULL,
    last_name VARCHAR(75) NOT NULL,
    role_id INT NOT NULL, 
    manager_id INT DEFAULT NULL,
    PRIMARY KEY (id)
  );