Databases Reference
In-Depth Information
3 The Business Intelligence Semantic Model
With the introduction of the Business Intelligence Semantic Model (BISM), there are now two separate
features that serve as Analysis Services databases in Microsoft SQL Server 2012: multidimensional
(ROLAP, MOLAP) databases, and tabular (initially introduced in the PowerPivot Add-in, versions 1
and 2). Each database and respective modeling features have the single goal of organizing disparate
data into an analytic model that effectively and efficiently supports the reporting and analysis needs
of the business.
Tabular modeling is supported by the xVelocity engine (formerly called Vertipaq). You can create a
semantic model by using Excel, PowerPivot in Excel 2013, or SQL Server Data Tools (formerly Business
Intelligence Development Studio [BIDS]). The result is a multidimensional model, an Excel or Power-
Pivot tabular model in a workbook.
The following are some resources that further explain the BISM model:
Microsoft SQL Server 2012 Analysis Services: The BISM Tabular Model
by Marc Russo, Alberto
Ferrari, Chris Webb (2012, Microsoft Press)
■
“What is BI Semantic model (BISM) in SQL Server 2012?,” which is available at
http://www.
■
“SQL Server 'Denali'-BI Semantic Model (BISM),” which is available at
http://blogs.msdn.com/b/
■
Tabular modeling vs. multidimensional modeling
Multidimensional modeling, introduced with SQL Server 7.0 OLAP Services and continuing through
SQL Server 2012 Analysis Services, makes it possible for BI professionals to create sophisticated
multidimensional cubes by using traditional Online Analytical Processing (OLAP). Multidimensional
modeling creates cubes composed of measures and dimensions based on data contained in a rela-
tional database. The OLAP engine uses the multidimensional model to pre-aggregate large volumes
of data to support fast query response times. The OLAP engine can store these aggregations on disk
with multidimensional OLAP (MOLAP) storage or store them in the relational database with relational
OLAP (ROLAP) storage.
Tabular modeling, introduced with PowerPivot for Microsoft Excel 2010, provides self-service data
modeling capabilities to business and data analysts. The tabular modeling experience is more acces-
sible to these users, many of whom have spent years working with data in desktop productivity tools
such as Excel and Microsoft Access.
Tabular modeling organizes data into related tables. If you want to use tabular modeling in SQL
Server Data Tools (SSDT) and provide server capacity for processing data, you must install Analysis
Services to operate in tabular mode.
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