 
create sequence movies_id_seq;
create table movies (
  id integer not null
    default nextval(movies_id_seq),
  name varchar(256) not null unique
    check (length(name) > 0),
  length_minutes integer not null
    check (length_minutes > 0),
  rating varchar(8) not null
    check (rating in ('Brak', 'G', 'PG', 'PG-13', 'R', 'NC-17')),
  primary key (id)
);


