create table employees (
  employee_id     int(11)         not null    auto_increment primary key ,
  department_id   int(11)         not null    default 0                  ,
  role_id         int(11)         not null    default 0                  ,
  manager_p       tinyint(1)      not null    default 0                  ,
  name            varchar(100)    not null    default ''                 ,

  -- rest of fields here
  --
  --

  index (department_id),
  index (role_id)
);

create table departments (
  department_id   int(11)        not null   auto_increment  primary key  ,
  name            varchar(100)   not null   default 'warehouse'

  -- rest of fields here
  --
  --

);

create table roles (
  role_id   int(11)        not null     auto_increment primary key  ,
  name      varchar(100)   not null     default ''

  -- rest of fields here
  --
  --
);