Dimensional Model question

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Dimensional Model question

Post  Jhonny on Mon Jul 16, 2012 8:38 am

Hi folks,

Before I ask my question, I would like to apologize for my bad english. English is not my native language.

So, i have to create a star schema dimensional model for a specific and separate data mart. It will be for a part of Sale business process.

I have the following preliminary dimensions: Date, Material (or Product), Channel Sales. The Material Dimension has a hierarchy one level above it: Material Group. But in my facts tables the grain is Material.

My problem is about the Material Group entity. Material Group has two important attributes: 'Max Discount' and 'Mark up'. These attributes have irregular updates that i will probably keep the history, so we can consider it a fast changing dimension i think.

So, Are these attributes really attributes or measures?

Do i snowflaking 'Material Group' in another dimensional? Do I keep 'Material Group' and its attributes in 'Material' Dimension ? Do I need to create another fact (or a factless fact table i dont know) to put these two information? Do I put them in a bridge dimension or a mini-dimension?

Tks.

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Re: Dimensional Model question

Post  ngalemmo on Mon Jul 16, 2012 2:39 pm

I would make material group a dimension and add an FK to it in the fact.

Max Discount is an attribute. The actual discount given would be a measure in the fact table.

Not sure about markup. I would store it as an attribute, but also place it as a measure in the fact so you know the markup at the time of sale.
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Re: Dimensional Model question

Post  Jhonny on Tue Jul 17, 2012 4:22 pm

ngalemmo, Tks a lot for the reply.

About 'Material Group', Should I create this dimension without connection(FK) with 'Material' dimension? So the Material and Material Group relationship will keep in the fact table, right?


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Re: Dimensional Model question

Post  ngalemmo on Tue Jul 17, 2012 5:40 pm

Yes or you place material group attributes in the material dimension itself.
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Re: Dimensional Model question

Post  sgudavalli on Fri Jul 20, 2012 7:14 am

ngalemmo; if you place material group attributes in the material dimension dont you think we need to handle the fast changing material group changes in the material dimension

assuming your 1st answer to be the rite one; create a seperate material group dimension and associate it directly to fact...

this way your model is simple star...

Johnny; I vote for it! create material group dimension without connection(FK) with 'Material' dimensio & the Material and Material Group relationship is available in the fact table

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