Mislio sam na moj primer podataka:
Kôd:
test=# insert into dpt values (1, 2, 10);
INSERT 0 1
test=# insert into dpt values (1, 2, 10);
INSERT 0 1
test=# insert into dpt values (2, 1, 10);
INSERT 0 1
test=# insert into dpt values (2, 1, 10);
INSERT 0 1
test=# insert into dpt values (1, 3, 10);
INSERT 0 1