text: DROP DATABASE IF EXISTS team_db;
  CREATE DATABASE team_db;
  
  USE team_db;
  
  CREATE TABLE department(
      id INT PRIMARY KEY NOT NULL AUTO_INCREMENT,
      department_name VARCHAR(30) NOT NULL
  );
  
  CREATE TABLE role(
      id INT PRIMARY KEY NOT NULL AUTO_INCREMENT,
      title VARCHAR(30),
      salary DECIMAL,
      department_id INT,
      FOREIGN KEY (department)
      REFERENCES department(id)
      ON DELETE SET NULL
  );
  
  CREATE TABLE employee(
      id INT PRIMARY KEY NOT NULL AUTO_INCREMENT,
      first_name VARCHAR(30),
      last_name VARCHAR(30),
      roles_id INT,
      manager_id INT,
  );