Question About Snowflaking

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Question About Snowflaking

Post  bciampa on Mon Mar 05, 2012 11:08 am

Hi,

I'm fairly new to the world of data warehousing and I have a question about snowflaking. I understand that snowflaking a dimension can reduce the space needed to store certain dimension attributes. However, what would keep a data architect from placing the foreign key to that snowflaked dimension directly into the fact table so that it can be joined to the fact table (in essence avoiding the snowflake design)?

Thanks,
Brian Ciampa

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Re: Question About Snowflaking

Post  boernard on Mon Mar 05, 2012 11:15 am

By placing the FK in the Fact table the "snowflaked" table becomes a dimension.

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Re: Question About Snowflaking

Post  bciampa on Mon Mar 05, 2012 11:47 am

Yes, thanks so much. I understand that is what is happening. If this is a possibility, why might a data architect choose to snowflake the dimension instead of joining it directly to the fact table?

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Re: Question About Snowflaking

Post  boernard on Mon Mar 05, 2012 12:33 pm

this article explains some cases where it might be better to go with snowflaking:

http://www.kimballgroup.com/html/articles_search/articles2001/0106IE.html?TrkID=IE200106

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Re: Question About Snowflaking

Post  bciampa on Mon Mar 05, 2012 2:03 pm

This is great. Thanks so much for introducing me to this article.

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