-- stlpec na vyznacenie toho, ze jeden billitem uz je zahrnuty/zauctovany v inom (#107178)
ALTER TABLE billitems ADD COLUMN billitem_parent INT REFERENCES billitems (id) ON UPDATE CASCADE ON DELETE SET NULL;
CREATE INDEX billitems_billitem_parent ON billitems (billitem_parent) WHERE billitem_parent IS NOT NULL;
COMMENT ON COLUMN billitems.billitem_parent IS 'odkaz na polozku billitems, v ktorej uz bola tato polozka obsiahnuta';
