MOLAP, ROLAP and HOLAP
MOLAP (Multi-dimensional online analytical processing) is a type of OLAP. The other type is ROLAP (relational online analytical processing). BI reporting and analysis tools in the old days implemented either MOLAP feature or ROLAP feature. The tools were also described as MOLAP tool or ROLAP tool. But now the BI reporting and analysis tools are equipped with both MOLAP and ROLAP features and hence they are also referred to as HOLAP (Hybrid OLAP) tool. As these concepts are already extensively written about in various other places I will just highlight the major differences MOLAP - All the possible combinations of calculations are pre-calculated and the calculated data is stored as cubes to enable faster/shorter refresh time at the time of query. ROLAP - Data is stored in relational format (RDBMS) but using dimensional modeling technique to make it look like a cube without a physical cube, no pre-calculations, this is to avoid unnecessary storage of calculated data th...
