text: DROP TABLE IF EXISTS department;
  DROP TABLE IF EXISTS role;
  DROP TABLE IF EXISTS employee;
  
  CREATE TABLE department (
    id INT NOT NULL AUTO_INCREMENT,
    name VARCHAR(45) NULL,
    PRIMARY KEY (id)
  );
  
  CREATE TABLE role (
    id INT NOT NULL AUTO_INCREMENT,
    title VARCHAR(45) NULL,
    salary DECIMAL(10.3) NULL,
    department_id INT NULL,
    PRIMARY KEY (id)
  );
  
  CREATE TABLE employee (
    id INT NOT NULL AUTO_INCREMENT,
    first_name VARCHAR(45) NULL,
    last_name VARCHAR(45) NULL,
    role_id INT NULL,
    manager_id INT NULL,
    PRIMARY KEY (id)
  );
  
  
  
  