text: DROP DATABASE IF EXISTS db_company;
  CREATE DATABASE db_company;
  USE db_company;
  
   CREATE TABLE department(
    id INTEGER AUTO_INCREMENT NOT NULL,
    name VARCHAR(30),
    PRIMARY KEY(id)
  );
  
  CREATE TABLE role(
    id INTEGER AUTO_INCREMENT NOT NULL,
    title VARCHAR(30),
    salary DECIMAL,
    departmentId INTEGER,
    PRIMARY KEY (id),
    CONSTRAINT department_fk FOREIGN KEY (departmentId) REFERENCES department(id) ON DELETE CASCADE
  );
  
  CREATE TABLE employee(
    id INTEGER AUTO_INCREMENT NOT NULL,
    firstName VARCHAR(30),
    lastName VARCHAR(30),
    roleId INTEGER,
    managerId INTEGER,
    PRIMARY KEY (id),
    CONSTRAINT role_fk FOREIGN KEY (roleId) REFERENCES role(id)  ON DELETE SET NULL,
    CONSTRAINT manager_fk FOREIGN KEY (managerId) REFERENCES employee(id) ON DELETE SET NULL 
  );
  