text: DROP DATABASE employee_trackerDB;
  
  CREATE DATABASE employee_trackerDB;
  
  USE employee_trackerDB;
  
  CREATE TABLE department
  (
      id INT AUTO_INCREMENT,
      name VARCHAR (30),
      PRIMARY KEY (id)
  );
  
  CREATE TABLE position
  (
      id INT NOT NULL AUTO_INCREMENT,
      title VARCHAR (30),
      salary DECIMAL (9,2),
      department_id INT,
      PRIMARY KEY (id),
      FOREIGN KEY (department_id) REFERENCES department (id)
  );
  
  CREATE TABLE employee
  (
      id INT AUTO_INCREMENT,
      first_name VARCHAR (30),
      last_name VARCHAR (30),
      position_id INT NULL,
      manager_id INT NULL,
      PRIMARY  KEY (id),
      FOREIGN KEY (position_id) REFERENCES position (id),
      FOREIGN KEY (manager_id) REFERENCES employee (id)
  );
  
  /**
      department:
      id - INT PRIMARY KEY
      name - VARCHAR(30) to hold department name
      
      role:
      id - INT PRIMARY KEY
      title - VARCHAR(30) to hold role title
      salary - DECIMAL to hold role salary
      department_id - INT to hold reference to what department role belongs to
  
      employee:
      id - INT PRIMARY KEY
      first_name - VARCHAR(30) to hold employee first name
      last_name - VARCHAR(30) to hold employee last name
      role_id - INT to hold reference to employee role
      manager_id - INT to hold reference to another employee that is manager of current employee, this field may be NULL if employee has no manager
      */