text: DROP DATABASE IF EXISTS unique_employee_tracker_db; 
  
  CREATE DATABASE unique_employee_tracker_db; 
  
  USE unique_employee_tracker_db;
  
  CREATE TABLE department(
    id INTEGER NOT NULL AUTO_INCREMENT,
    name VARCHAR(30) NOT NULL,
    PRIMARY KEY (id)
  );
  
  CREATE TABLE role(
    id INTEGER NOT NULL AUTO_INCREMENT,
    title VARCHAR(30) NOT NULL,
    salary DECIMAL NOT NULL,
    department_id INTEGER NOT NULL,
    PRIMARY KEY (id)
  );
  
  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,
    PRIMARY KEY (id),
    FOREIGN KEY (role_id)
          REFERENCES role(id),
      FOREIGN KEY (manager_id)
          REFERENCES employee(id)
  );