OLAP - Most queries need an aggregate of records. Generally you do NOT need most records, but simply the records grouped by dimensions per interval (for almost

OLAP - Most queries need an aggregate of records. Generally you do NOT need most records, but simply the records grouped by dimensions per interval (for almost all olap reporting). You do not change the data, you observe it. If you change it, you are not dealing with OLAP data. OLTP - You are dealing with the ins and outs of people using stuff to do things. You buy something, you check out something, you some way perturb the state of things. This should not require large amount of row lookups in 99.9% of cases.