Mining cubes vs relational

I've not found much guidance so far about the pros and cons of mining OLAP cubes vs their underlying fact and dimension tables. Can anyone offer advice in this area, or point me to more info about this?

Thanks,
Kevin

Generally I recommend mining OLAP cubes when you are mining results that OLAP is good at producing, otherwise you should mine relational tables. OLAP is not particularly good at returning large amounts of detail data. However, if you were mining stores, for example, and your inputs were total sales of products for particular months/categories, or even sales acceleration of such by store, those measures are very difficult and slow to obtain through relational means, and I would recommend OLAP.

Another issue with OLAP MM's is that there really isn't any way to split data into training and validation sets. If this is a requirement, and you need to use the aggregation/calculation facilities of OLAP, you can get the OLAP results into a table, split into training and validation sets, and then mine the resultant relational table.

sql

Migration Wizard Error

Hi !,

The migration of OLAP cubes with aggregations to SSAS, generate the following error:

"Another 'Aggregation' object has the '31 3314' ID."

and then the migration process stops.

The dimension structure is changed during the process and a posible solution is deleting all the aggregation before migration.

But I would like to know if it is really a bug or there is a known reason for getting such error.

Thanks in advance !!!

Leandro

Looks like you somewhow got 2 aggregations in AS2000 with the same name.

Now, when trying to migrate AS2005 trying to create aggregations for you and stops at the point when meets aggregation with the duplicate name.

Several options.

Try and get rid of the duplicate aggregation using Parition Manager sample application shipped with SQL Server 2000 resource kit.

Try re-desingn aggregations using Analysis Manager.

Edward.
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This posting is provided "AS IS" with no warranties, and confers no rights

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That's right.

So Instead of migrating directly from a production server, would it be better to copy AS2000 objects to another database/server, clean all duplicate aggregations, and then run the migration wizard ?.

We have high volume partitions, but fortunately users dont browse freely the cubes. An application runs a lot of specific MDX queries. So we decided to design aggregations manually because generating an aditional one was too costly and it was better to define a lower-level aggregation that serves two similar types of MDX queries, than adding two aggregations by using the Usage Based Optimization.

I dont know If the last algorithm was optimized to support such type of aggregations design criteria.

Thanks very much.

Leandro

Thanks Edward,

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I would definitely try make sure that any modifications are done in the test environment.

Edward.
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This posting is provided "AS IS" with no warranties, and confers no rights

migration of Static cubes in 2000

Hello,

We have some cubes in sql server 2000 that are static and cannot be reprocessed in 2005. I am wondering if anyone had dealt with a way to migrate them to AS 2005?

Thanks,

Fedwa

Can you please clarify what does "static" cube means ?