text: DROP DATABASE IF EXISTS company_db;
  CREATE DATABASE company_db;
  
  USE company_db;
  
  CREATE TABLE department (
      id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
      department_name VARCHAR(30) NOT NULL
  );
  
  CREATE TABLE roles (
      id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
      title VARCHAR(30) NOT NULL,
      salary DECIMAL NOT NULL,
      department_id INT NOT NULL,
      FOREIGN KEY (department_id)
      REFERENCES department(id)
      
  );
  
  CREATE TABLE employee (
      id INT NOT null AUTO_INCREMENT PRIMARY KEY,
      first_name VARCHAR(30) NOT NULL,
      last_name VARCHAR(30) NOT NULL,
      role_id INT,
      manager_id INT,
      FOREIGN KEY (role_id)
      REFERENCES roles(id),
      FOREIGN KEY (manager_id) 
      REFERENCES employee(id)
      
  );
  