Introduction to Multidimensional Data Model Design - SQL Server Analysis Services 2012 Cube Development - page 7

In most environments, both cubes and Tabular Models will be used as each provides
a useful and specific set of functionality. Determining which should be used for a giv-
en set of requirements will depend on the particulars of those requirements, but the
following checklist provides a high-level guideline for selecting the most appropriate
tool.
A Cube is best if the following requirements are satisfied (not a comprehensive list,
more of a top five):
• You need Writeback functionality : Writeback is most commonly used for
budgeting and what-if analysis. It's not the most widely used functionality but
can be a very important part of some BI environments. This functionality is
not currently supported in the Tabular Model.
• You have complex calculations : It's difficult in DAX to create complex cal-
culations, which are relatively straightforward in MDX.
• You plan to have Named sets : Named sets are very useful and user
friendly. However, they are not currently supported in Tabular Models.
• You have Many-to-Many relationships : While many-to-many relationships
are possible in Tabular Models, they are complicated to set up, whereas in
cubes these relationships are native and relatively easy.
• You will use Role Playing Dimensions : Like many-to-many relationships,
Role Playing Dimensions are possible in Tabular Models, but they are com-
plex to set up and also not very intuitive for users.
A Tabular Model is best if the following requirements are satisfied (again, not a com-
prehensive list):
• You need the ability to quickly add additional or external data : The Tab-
ular Model allows you to connect to a wide variety of sources, while the cube
is far more constrained on its source requirements. The Tabular Model also
offers greater data compression compared to the multidimensional model.
Generally, the cycle for Tabular Model development will be shorter compared
to that for multidimensional model development.
• Your model is relatively simplistic : As mentioned earlier, complex design
scenarios, such as many-to-many relationships as well as parent-child or role
playing dimensions can be implemented with the Tabular Model, but it would
require much greater effort compared to the effort with the multidimensional
model.