create table u_dir(
  id integer not null constraint u_dir_pk primary key,
  name varchar(50) not null,
  owner integer constraint u_dir_fk references u_dir(id) on delete cascade on update cascade
  );


create table people(
  id integer not null constraint people_pk primary key,
  sirname integer not null constraint people_fk1 references u_dir(id),
  name integer not null constraint people_fk2 references u_dir(id),
  lastname integer not null constraint people_fk3 references u_dir(id),
  address varchar(100) not null,
  sex integer not null,
  doc varchar(20) not null constraint people_uk1 unique,       /*pasport*/
  pol_num varchar(20) not null constraint people_uk2 unique,   /*Strah. polic*/
  date_of_birth date not null
  );