text: DROP DATABASE IF EXISTS employee_tracker_db;
  CREATE DATABASE employee_tracker_db;
  USE employee_tracker_db;
  
  CREATE TABLE department (
  id INT(100) NOT NULL AUTO_INCREMENT,
  department_name VARCHAR(30) NOT NULL,
  PRIMARY KEY (id)
  );
  
  CREATE TABLE employee_role (
  id INT(100) NOT NULL AUTO_INCREMENT,
  title VARCHAR(30) NOT NULL,
  salary DECIMAL(8,0) NULL,
  department_id INT(100) NOT NULL,
  PRIMARY KEY (id)
  );
  
  CREATE TABLE employees (
  id INT(100) NOT NULL AUTO_INCREMENT,
  first_name VARCHAR(30) NOT NULL,
  last_name VARCHAR(30) NOT NULL,
  role_id INT(100) NOT NULL,
  manager_id INT(100) NULL,
  PRIMARY KEY (id)
  );
  