text: DROP DATABASE IF EXISTS employee_trackerDB;
  
  CREATE DATABASE employee_trackerDB;
  
  USE employee_trackerDB;
  
  CREATE TABLE department (
    id INT NOT NULL AUTO_INCREMENT  PRIMARY KEY,
    name VARCHAR(30) 
  );
  
  CREATE TABLE role (
    id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
    title VARCHAR(30) NULL,
    salary DECIMAL(10,2) NULL,
    department_id INT NULL,
  
    FOREIGN KEY (department_id) REFERENCES department(id)
  );
  
  CREATE TABLE employee (
    id INT NOT NULL AUTO_INCREMENT  PRIMARY KEY,
    first_name VARCHAR(30) NULL,
    last_name VARCHAR(30) NULL,
    manager_id INT,
    role_id INT,
    FOREIGN KEY (role_id) REFERENCES role(id),
    FOREIGN KEY (manager_id) REFERENCES employee(id)
    );
    
  SELECT * FROM department;
  
  SELECT * FROM role;
  
  SELECT * FROM employee;
  
  