text: DROP DATABASE IF EXISTS employee_tracker_db;
  CREATE DATABASE employee_tracker_db;
  
  USE employee_tracker_db;
  
  CREATE TABLE departments(
      id INT NOT NULL AUTO_INCREMENT,
      name VARCHAR(30) NOT NULL,
      PRIMARY KEY(id)
  );
  
  CREATE TABLE roles (
      id INT NOT NULL AUTO_INCREMENT,
      title VARCHAR(30) NOT NULL,
      salary DECIMAL(10,4) NOT NULL,
      department_id INT NOT NULL,
      PRIMARY KEY(id),
      FOREIGN KEY(department_id) REFERENCES departments(id) ON DELETE CASCADE
  );
  
  CREATE TABLE employee(
      id INT NOT NULL AUTO_INCREMENT,
      first_name VARCHAR(30) NOT NULL,
      last_name VARCHAR(30) NOT NULL,
      role_id INT NOT NULL,
      manager_id INT NULL,
      PRIMARY KEY(id),
      FOREIGN KEY(role_id) REFERENCES roles(id) ON DELETE CASCADE,
      FOREIGN KEY(manager_id) REFERENCES employee(id)
  );
  
  
  select * from departments;
  SELECT * FROM  roles;
  SELECT * FROM employee;