CODEWITHSUNDEEP
databasessasolap
John
John

Reputation: 503

How is technically resolved SSAS OLAP cube?

i am new to SSAS platform. I am curious about how it is technically solved.

I heard that SQL query is not working on this OLAP (MOLAP). Is it true?

I imagined that it is in technical way just some standard DB table of facts with links to dimension DB tables.

Am I wrong?

Where are that data?

In RAM or on hard drive?

Are they structured in classic DB model or in another way?

Upvotes: 0

Views: 343

Answers (2)

Diego
Diego

Reputation: 36176

no, you cant run standard T-SQl queries on a SSAS database, you must run MDX queries (the syntax is different but it remembers T-SQl queries)

You mentioned MOLAP. MOLAP is one of 3 ways a SSAS databse can store data, the others are HOLAP and ROLAP. No matter whihc storage mode you choose, my first statment is valid, you must query your DB using MDX, not T-SQL.

The data is on files on your file share as it is on your OLTP database. If you go to your instance folder, there is a folder called data where all the data is.

Upvotes: 0

Stacia
Stacia

Reputation: 7218

Analysis Services stores MOLAP data in a structure that is completely different from a relational database. You use a relational database as a source, but the data is copied, compressed, indexed, and restructured in such a way as to optimize storage and retrieval. There is physical storage required. SSAS also takes advantage of RAM and holds what it can there to be more responsive to queries. It is possible to keep source data in a relational database if you set up partitions to use ROLAP storage, but generally better performance is gained by using MOLAP storage.

For more information, see:

http://technet.microsoft.com/en-us/library/ms174915.aspx

http://www.sql-server-performance.com/2009/ssas-storage-modes/

http://www.bidn.com/blogs/dustinryan/ssis/872/ssas-2008-storage-modes

Upvotes: 1

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