Someone

create table bestelling
(
  bestel_id number (10) constraint c_t_bestelling_pk_bestel_id
        primary key,
  klant_id number (10) constraint c_t_bestelling_fk_klant_id
        foreign key references klant(klant_id),
  product_id number(10) constraint c_t_bestelling_fk_product_id
        foreign key references product(product_id),
  aantal_besteld number(6),
  datum_besteld timestamp default sysdate,
  bestel_status number(4)
);