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