Introduction

In this chapter, you'll learn how to create OLAP (short for Online Analytical Processing) schemas for Pentaho with MongoDB as a data source. OLAP is an approach to creating multidimensional analyses. Pentaho uses the ROLAP (short for Relational Online Analytical Processing) engine, called by Mondrian to convert MDX (short for Multidimensional Expressions) queries into SQL queries.

If you aren't a business intelligence consultant, you probably have never heard about data warehouse and the preceding terms. Essentially, a data warehouse is a system for storing historical data from different data sources, so that you're prepared to use reporting systems, for example, Pentaho and Mondrian. This is a quick and simple explanation, but it is recommended that you carry out research about these terms, as this book is focused on using Pentaho and MongoDB, and not business intelligence technologies.

As Mondrian is responsible for generating SQL queries and MongoDB does not support it, it...