text: DROP DATABASE IF EXISTS employee_DB;
  CREATE database employee_DB;
  USE employee_DB;
  CREATE TABLE departments (
      id INT AUTO_INCREMENT NOT NULL PRIMARY KEY,
      name VARCHAR(30)
  );
  CREATE TABLE roles (
      id INT  NOT NULL AUTO_INCREMENT PRIMARY KEY,
      title VARCHAR(30) NOT NULL,
      salary DECIMAL(10,2) NOT NULL,
      department_id  INT NOT NULL
  );
  CREATE TABLE employees (
      id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
      first_name VARCHAR(30) NOT NULL,
      last_name VARCHAR(30) NOT NULL,
      role_id INT NOT NULL,
      manager_id INT NULL
  );
  
  
  