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Wednesday, March 13, 2013

What is Periodic Fact Table In Datawarehousing

A periodic fact table will store one row for a group of transaction for a specific time; this is how it differs from transaction table. In Transaction table we have separate rows for each transaction whereas here we group it with respect to day, week, month, or quarter, depending on which factor we need to store the Transactions as a whole. Compared to Transaction tables, periodic fact table will grow slowly in size.

Below we have five records, about the Product Order Cost for a particular day in Order Cost Table

    Product_Order_Cost: $1000, Day1 ,10PM
    Product_Order_Cost: $300, Day1 ,12PM
    Product_Order_Cost: $600, Day1 ,1AM
    Product_Order_Cost: $900, Day1 ,4AM
    Product_Order_Cost: $900, Day1 ,7AM

In case of Transaction tables we will have five separate records in Order Cost Table. If it’s a periodic fact table then we will store on basis of a period of time like day, week or year.

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