Introduction

Prior to the introduction of tabular modeling, which is now commonly known as Business Intelligence Semantic Models (BISM), Microsoft relied on its multidimensional storage model (MOLAP) for Analysis Services (analytical) database. In fact, multidimensional refers to a method of storage, which is still a viable option for enterprise business intelligence through SQL Server Analysis Services (SSAS). The term BISM is not unique to tabular modeling—it also relates to the semantic abstraction of a data model within the MOLAP engine. However, whenever BISM is discussed, it usually relates to tabular modeling (whether that be in PowerPivot or SSAS with a tabular storage mode). The storage engine for tabular modeling is also referred to as xVelocity.

Unlike the xVelocity engine of tabular models, the multidimensional model was basically designed to use a relational source (preferably a SQL Server) as its data source. Additionally, the multidimensional engine assumed that data...