CODEWITHSUNDEEP
data-modelingdata-warehousedatamodel
davidjhp
davidjhp

Reputation: 8016

How to design a database model for a large data warehouse?

Lets say I design a database model for an online seller such as Amazon:

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Next, to create the database model for the larger data warehouse, I flatten the Order and OrderDetails tables, and flatten the Product and Vendor tables:

enter image description here

I do this to apply the concept of designing models for parent-child applications, as described here http://bit.ly/1bOuOXQ

The data in the data warehouse tables becomes repetitive:

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Several values such as $76.30 for OrderTotal repeat on each row, is this correct? Is the model correct?

Upvotes: 1

Views: 1498

Answers (2)

Moog
Moog

Reputation: 10193

Each row represents a match for each product, the corresponding order subtotal and total will be identical for each row with a specific orderid.

The result is as expected for your model definition.

Upvotes: 3

Paul Draper
Paul Draper

Reputation: 83205

Yes.

OrderTotal is the same for all records, so it is duplicated when you put everything in a single spreadsheet.

(Of course, in a relational database you are keep data in several tables, so it isn't duplicated.)

Upvotes: 1

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