OLAP is a database functionality that allows database analysts to perform different types of analysis on data from multiple sources.
The OLAP system works in a very efficient manner, data from different sources are collected together in a data warehouse. Data collected from different sources is then cleaned and stored in the form of data cubes. Different types of operation can be performed on OLAP systems which are Roll-up, Drill-down, Slice, Dice, and Pivot.
There are different types of OLAP systems, these types are:
Multi-Dimensional (MOLAP) OLAP
Briefly, MOLAP is the type of OLAP in which data is directly indexed in the multi-dimensional databases. In ROLAP, data is stored in the relational database on which different OLAP queries are performed. Hybrid OLAP is the combination of MOLAP and ROLAP with a greater processing capability as compared to both of them.