text: DROP DATABASE IF EXISTS cms_db;
  
  CREATE DATABASE cms_db;
  
  USE cms_db;
  
  CREATE TABLE department (
      id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
      name VARCHAR(30) NOT NULL
  );
  
  CREATE TABLE role (
      id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
      title VARCHAR(30) NOT NULL,
      salary DECIMAL NOT NULL,
      department_id INT,
      FOREIGN KEY (department_id) 
      REFERENCES department(id)
      ON DELETE SET NULL
  );
  
  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 role(id)
      ON DELETE SET NULL
  );