To summarize, tabular model is simple, keeps data entirely in memory, providing exciting performance potential without any special tuning vs. Dimensional modeling and MDX language create has a steep learning curve, but natively provide more complex capabilities.Native support for Parent-child hierarchy or many-many relationships as opposed to tabular model where you need a complex work around.Your solution requires complex modeling or the dataset is extremely large.Support for Write-back, Actions, Custom Assemblies, Custom Rollups, Custom Drillthrough Actions, Linked objects, Parent-child hierarchy, or Translations.Use MOLAP storage, data stored in compress format it pre-calculates aggregates and uses bitmap indexes.You want to use MDX as it is more powerful and has more features (complex calculations, scoping, and named sets etc.) than DAX.When your source is based on dimensional modeling, has dimensions and facts, has complex relationships and has a very large volume of data.Tabular modeling and DAX language has a less steep learning curve, but complex capabilities may require sophisticated DAX expressions to be written.It is faster to develop and less expensive to use in terms of time, resources and skill requirement.You want to use Power View for reporting.No support for Write-back, Actions, Custom Assemblies, Custom Rollups, Custom Drillthrough Actions, Linked objects, or Translations.This reason for this is because the results of DAX queries are never stored within the cache which means that a DAX query will always take the same time to execute whenever it is run whereas the multi-dimensional model keeps the query results in cache and as such the more the cube is used, the better query performance you will get on subsequent query executions. In-memory column store storage gives great performance, but that does not mean the tabular model will always be faster than the multi-dimensional model. Uses VertiPaq (xVelocity) engine for in-memory column store storage, data is stored in a highly compressed format which means it does not require pre-calculated aggregates, bitmap indexes etc.You want to use DAX for scripting much easier to learn than MDX.When your source is based on relational database modeling and has basic (1:N) relationships one single model can pull data directly from multiple external sources without the need of ETL.Please note, some of the scenarios may change in future releases, for example currently Power View works against the tabular model only, but in the future it might work against the multi-dimensional model as well: Tabular.which one to chooseĪlthough there are no straight forward rules/guidelines for choosing one or the other, I have listed below some of the scenarios from my experiences (though this is not a comprehensive list). a tabular model, so let discuss these items first before we start creating a tabular model project. It uses this workspace database as temporary storage for data, while you develop the model by importing data from the underlying data sources and designing objects that organize, enhance, and secure the data.Īt this point, some people might think why include tabular modeling now, when should we use a multi-dimensional model vs. When we create a project based on the tabular model, SQL Server Data Tool (SSDT) adds a Model.bim file to the project and creates a workspace database on the Analysis Services instance (installed in tabular mode) that we specify. Tabular model is a new type of analysis services database structure that Analysis Services supports in SQL Server 2012. This foundation provides both multi-dimensional as well as tabular data modeling capabilities, to offer the best of both worlds and also a choice to the solution designer/developer which is called the BI Semantic Model (BISM). the multi-dimensional model hence it makes sense to embrace the relational/tabular data modeling for broader adoption and to ensure utilization of a customers' existing investments and skills available. The tabular model is relatively easy to understand and is used by a large group of developers vs. Analysis Services in SQL Server 2012 can be either deployed in a multi-dimensional model for creating multi-dimensional and data mining projects or tabular model mode for creating a tabular/relational project (note: there is also a third option for PowerPivot for SharePoint as well).
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