1. Chris Webb Crossjoin Consulting Ltd chris@crossjoin.co.uk
Basic BISM
Chris Webb
Crossjoin Consulting Ltd

2. Who Am I? Chris Webb chris@crossjoin.co.uk
Independent Analysis Services consultant and trainer
Author: “MDX Solutions” and “Expert Cube Development with SSAS 2008”
SQL Server MVP
Blogger:

3. Agenda What is BISM? Tabular vs Multidimensional positioning
Building a Tabular Model
Demos, demos, demos…

4. What is BISM? BISM = BI Semantic Model
It’s the new UDM (if you remember that)
The product is still officially called SQL Server Analysis Services
SSAS now has two design experiences:
Multidimensional models, ie cubes
Tabular models, a ‘corporate’ version of what we have with PowerPivot
BISM = Multidimensional + Tabular

5. Tabular vs Multidimensional
It’s an either/or choice at the moment:
An instance can only be one or the other
A project can only be one or the other
Though in the future we may be able to have a single database that can be viewed or designed in both ways

6. Tabular Pros Represents the future
Concepts easier to understand for those with a relational/SSRS background
Speed of the Vertipaq storage mode
Support for Project Crescent
DirectQuery = ROLAP done right (hopefully)
Ability to import existing PowerPivot models
No more processing-this-unprocesses-that dependencies

7. Tabular Cons Version 1.0 product, therefore immature
DirectQuery has a lot of limitations
No parallel processing for partitions -> big impact on processing times
No display folders and other ‘nice to have’ stuff
Vertipaq effectively limited by RAM available on the server
Some paging options, but performance suffers
DAX still unable to do the same kind of complex calculations that MDX Scripts can

8. Multidimensional Cons
Regardless of the official line, unlikely ever to get much priority for new features
Very few new features in Denali
No support for Crescent yet (though coming at some point)
No integration with PowerPivot
Cubes are just too confusing for some developers
Old technology

9. Multidimensional Pros
Mature technology, well understood and well resourced in the marketplace
MDX Scripts allow for complex calculations
Disk-based model allows for greater scalability at the very high-end than Vertipaq
Allows for complex modelling, eg many-to-many relationships

10. Creating a New Tabular Project
Tabular projects require Visual Studio 2010
Projects are built in three ways:
Start from scratch
Import from PowerPivot
Import from an existing Tabular model
Projects consist of a single .bim file, plus some hidden files and folders

11. Importing Data Into Tables
All the data sources that PowerPivot supports are present in the Tabular model
So you get more supported datasources that with Multidimensional, eg Odata
Data can be imported by either
Selecting tables and then filtering in the UI
Writing your own SQL/MDX
Tables can be partitioned
You can create calculated columns with DAX

12. Workspace Databases
Workspace databases are a ‘working copy’ of your database that allow you to see your data while you model it
Probably hosted on a local SSAS instance, not a separate server (even your dev server)
Probably with a subset of your real data
Do not confuse this with your production or even your dev server!
Various options relating to whether it’s retained on the server, detached or deleted after you close BIDS
No cube browser in BIDS – you can open Excel direct from BIDS and browse your workspace database

13. Relationships
Relationships can be added between tables just as in PowerPivot
New relationship designer makes life much easier
Two tables can now have multiple relationships between them
eg Role-playing date dimension tables
Only one relationship is ‘active’
DAX has a UseRelationship() function to allow you to choose which one to use

14. Hierarchies
Values in a column can be sorted by using the Sort By Column property
eg for day or month names
Hierarchies can be built with drag and drop inside diagram view
No true support for parent/child hierarchies
But can be flattened using calculated columns and several new DAX functions like Path()

15. Measures
Simple measures (sums, counts etc) can be created with a single click
More advanced measures can be created with DAX expressions
Format strings have been replaced by separate properties
Measures are displayed in a grid under the table in BIDS (ugh)

16. DAX Queries
DAX is now a query language as well as a calculation language
Very different from MDX
Tabular models can still be queried with MDX
Much more suitable for detail-level reporting than MDX
Much more ‘relational’ – but not SQL
DAX queries will often perform better than MDX queries against the same model

17. DirectQuery DirectQuery is essentially ROLAP for Tabular
All queries are translated to SQL
Only works with SQL Server data sources
Several limitations:
Some DAX functions don’t work (eg time intelligence)
No calculated columns
No MDX queries, only DAX
Vertipaq/DirectQuery mixed mode possible
Data exists in both storage modes
One storage mode used by default
Clients can choose which storage they use with a connection string property

18. Security
Tabular models have something similar to Multidimensional dimension security
No cell security
Allow you to use DAX expressions to filter rows in tables for particular roles
Basic administrative security, can either
Read data and/or
Refresh data
Or be an administrator

19. Summary Tabular is very easy to get up and running
Suitable for 70% of SSAS projects today
Certainly good for all the small-scale or basic projects
Good if you never liked or understood cubes
Outperforms Multidimensional in most cases
Download the CTP3 demo VM!

20. Blogs Cathy Dumas http://blogs.msdn.com/b/cathyk/
Kasper de Jonge
Marco Russo
Alberto Ferrari