text: DROP DATABASE IF EXISTS employer_DB;
  CREATE database employer_DB;
  
  USE employer_DB;
  
  
  -- Create the table plans.
  CREATE TABLE department (
    id int NOT NULL AUTO_INCREMENT,
    name varchar(30) NOT NULL,
    PRIMARY KEY (id)
  );
  
  
  -- Create the table plans.
  CREATE TABLE role (
    id int NOT NULL AUTO_INCREMENT,
    title varchar(30) NOT NULL,
    salary DECIMAL(10,2),
    department_id int, 
    PRIMARY KEY (id),
    CONSTRAINT department_role FOREIGN KEY (department_id) REFERENCES department(id)
  );
  
  -- Create the table plans.
  CREATE TABLE employee (
    id int NOT NULL AUTO_INCREMENT,
    first_Name varchar(30) NOT NULL,
    last_name varchar(30) NOT NULL,
    role_id int,
    manager_id int,
    PRIMARY KEY (id),
    CONSTRAINT role_identification FOREIGN KEY (role_id) REFERENCES role(id),
    CONSTRAINT manager_identification FOREIGN KEY (manager_id) REFERENCES employee(id) ON DELETE SET NULL
    
  );
  
  
  
  