For incremental updating, OLAP checks for a corresponding tuple in the summary fact table. If absent, it is inserted; if present, its value is updated. In both cases, the result propagates up. MOLAP similarly performs incremental updating by checking for the corresponding cell in its cuboid. If absent, it is inserted; if present, its value is updated. In both cases, the result propagates up. HOLAP's approach is similar to either ROLAP or MOLAP, based on its dimensions' implementation techniques.