text: DROP DATABASE IF EXISTS employee_db;
  
  CREATE DATABASE employee_db;
  
  USE employee_db; 
  
  -- Create department table
  CREATE TABLE department(
      id INTEGER NOT NULL AUTO_INCREMENT,
      name VARCHAR(30) NOT NULL,
      PRIMARY KEY (id)
  );
  
  -- Create roles table
  CREATE TABLE roles(
      id INTEGER NOT NULL AUTO_INCREMENT,
      title VARCHAR(30) NOT NULL,
      salary DECIMAL NOT NULL,
      department_id INTEGER NOT NULL,
      PRIMARY KEY (id)
  );
  
  -- Create employee table
  CREATE TABLE employee(
      id INTEGER NOT NULL AUTO_INCREMENT,
      first_name VARCHAR(30) NOT NULL,
      last_name VARCHAR(30) NOT NULL,
      role_id INTEGER NOT NULL,
      manager_id INTEGER NULL,
      PRIMARY KEY (id)
  );