Using a Fact table like a dimension From another Fact table

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Using a Fact table like a dimension From another Fact table

Post  kepb on Thu May 05, 2011 1:25 pm

Hi i need a advice in my job have a datamart about sells which include information about
sells in dollars, sells in tons and also information about sellers like percent of money in base of their sells.

in the fact table almost all the columns are int but it have one text and is numberOrder (ex 001-5555) i undersand this
camp is aceptable.

but in order to implement "information about sellers like percent of money in base of their sells" we need somo extra columns
like "document State" (Ex canceled,send, not send,etc) and also "Document type " (ex DONATIONS ,free,etc)
and some others columns about "information of the document"

so my doubt if Implement those columns in the fact table my number of text columns increase in five is it ok or maybe for each extra column create a new dimension :S?
i know we can manage that using a dimension from the fact table (using SQL SERVER)
or maybe i can split my fact table an put in a NEw Dimension table like 'DIMCOMUMENT' in my model

i dont know which one is better
also we going to model a datamart of payments and we gonna need also information abour the document
and we can use this "NEw Dimension table" or maybe we can use the original fact table as a dimension of the new fact table
(this fact table belong to the new datamart of payments )

thanks


Last edited by kepb@hotmail.com on Thu May 05, 2011 1:31 pm; edited 1 time in total (Reason for editing : Forgot some letters)
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Re: Using a Fact table like a dimension From another Fact table

Post  hang on Sat May 07, 2011 7:45 am

Dimension conformance is the key to your problem. You should avoid having textual attribute in your fact table unless itís of very high cardinality, like your order number. Remove all the document related attributes and put them in one dimension with a surrogate PK which is also FK in all of your fact tables that share the same dimension.

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Re: Using a Fact table like a dimension From another Fact table

Post  kepb on Sun May 08, 2011 4:12 pm

So is better split my document information in one dimension with all caracteristics (text) of the document and leave in the fact table just the integer information like totals or taxes?
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Re: Using a Fact table like a dimension From another Fact table

Post  ngalemmo on Sun May 08, 2011 7:33 pm

kepb@hotmail.com wrote:So is better split my document information in one dimension with all caracteristics (text) of the document and leave in the fact table just the integer information like totals or taxes?

Not necessarily one dimension... particularly if you wind up with a dimension with almost as many rows as the fact.

Review the attributes and group like/highly correlated attributes together. You are much better off with a number of small dimensions than one big one.
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