text: DROP DATABASE IF EXISTS employee_trackerDB;
  CREATE database employee_trackerDB;
  
  USE employee_trackerDB;
  
  CREATE TABLE Departments (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(100) NULL
  );
  
  CREATE TABLE Roles (
    id INT AUTO_INCREMENT PRIMARY KEY,
    title VARCHAR(100) NULL,
    salary DECIMAL(12,2) NULL,
    department_id INT NULL, 
    FOREIGN KEY(department_id) REFERENCES Departments(id) ON DELETE SET NULL
  );
  
  CREATE TABLE Employees (
    id INT AUTO_INCREMENT PRIMARY KEY,
    first_name VARCHAR(100) NULL,
    last_name VARCHAR(100) NULL,
    role_id INT NULL, 
    manager_id INT NULL,
    FOREIGN KEY(role_id) REFERENCES Roles(id) ON DELETE SET NULL,
    FOREIGN KEY(manager_id) REFERENCES Employees(id) ON DELETE SET NULL
  );
  -- SELECT * FROM Departments;
  -- SELECT * FROM Roles;
  -- SELECT * FROM Employees;
  
  INSERT INTO Departments (name)
  VALUES ("Management");
  
  INSERT INTO Departments (name)
  VALUES ("Sales");
  
  INSERT INTO Roles (title, salary, department_id)
  VALUES ("Manager", 50000.50, 1);
  
  INSERT INTO Roles (title, salary, department_id)
  VALUES ("Sales", 43000.50, 2);
  
  INSERT INTO Employees (first_name, last_name, role_id, manager_id)
  VALUES ("Jacky","Doo",1,NULL),("Jane","Doe",2,1);
  
  ALTER TABLE employees DROP FOREIGN KEY employees_ibfk_2;
  