text: DROP DATABASE IF EXISTS employeeTracker;
  CREATE DATABASE employeeTracker;
  USE employeeTracker;
  
  CREATE TABLE department (
    id INT PRIMARY KEY AUTO_INCREMENT NOT NULL,
    name VARCHAR(30) NOT NULL
  );
  
  CREATE TABLE role (
    id INT PRIMARY KEY AUTO_INCREMENT NOT NULL,
    title VARCHAR(30) NOT NULL,
    salary DECIMAL(10, 2) NOT NULL,
    department_id INT NOT NULL,
    CONSTRAINT fk_department
      FOREIGN KEY (department_id)
          REFERENCES department(id)
              ON DELETE CASCADE
              ON UPDATE CASCADE
  );
  
  CREATE TABLE employee (
    id INT PRIMARY KEY AUTO_INCREMENT NOT NULL,
    first_name VARCHAR(30) NOT NULL,
    last_name VARCHAR(30) NOT NULL,
    role_id INT,
    manager_id INT,
    CONSTRAINT fk_role
      FOREIGN KEY (role_id)
          REFERENCES role(id)
              ON DELETE SET NULL
              ON UPDATE CASCADE
  );
  