Question on breaking out Degenerate Dimension to separate dimension

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Question on breaking out Degenerate Dimension to separate dimension

Post  mru22 on Tue Dec 13, 2011 1:38 pm


I currently have a Claim Payment Fact Table that has on degenerative dimension for a "PaymentNumber"

Table ClaimPaymentFact


ClaimPaymentKey
ClaimKey
ClaimPaymentTypeKey
PaymentNumber
..etc

The client now needs 3 additional non fact columns from the Operational Table that would also translate directly to the fact table based on where the data is sourced.

the new columsn are

1) Transcation Number
2) Payee Name
3) Journal Voucher Code


The cardinality is moderate so I was thinking of making a new dimesion and adding those three columns plus moving down payment into the new dimension.

Or am I better off having three more non fact columns in the fact table.

If I do make a new dimension, what would be considered the natural key from the Source ?

Thanks

mru22

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Re: Question on breaking out Degenerate Dimension to separate dimension

Post  John Simon on Sun Dec 18, 2011 8:04 am

Create a separate dimension based on the transaction key. Most likely this table will only ever be used to get the detail on a small number of records in a drill through situation. If you put then in the fact table performance of other queries on that fact table would degrade for no good reason.

John Simon

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