text: prompt - table drs_rental
  
  create table drs_rental (
    rental_id       integer generated by default on null as identity,
    rental_date     date                 not null ,
    inventory_id    integer              not null ,
    customer_id     integer              not null ,
    return_date     date    default null          ,
    staff_id        integer              not null ,
    last_update     date                 not null ,
    --
    primary key (rental_id),
    unique      (rental_date, inventory_id, customer_id)
  );
  
  