CODEWITHSUNDEEP
data-warehousebusiness-intelligencedimensional-modeling
Arman Nouromid
Arman Nouromid

Reputation: 11

Design a Relation Ships For Data Warehouse

I'm going to design a DataWarehouse for Northwind Database, but my customer and product and employee tables have two common fields called country and city. I want to find out that it is correct to define the relationship between dimension Geo and 3 Other Dimensions according to the diagram form? If you have any comments please share

My DataWareHouse Diagram

Upvotes: 0

Views: 67

Answers (1)

nsousa
nsousa

Reputation: 4544

It depends on what phylosophy you want to implement. If you follow Kimball you want a star schema, where fact tables are connected to dimensions and those don’t connect to anything else. In that case you’re better off keeping the geo fields in each dimension.

Any redundancy is meaningless as normally all dimensions combined are much smaller in size than the fact table(s), probably a few percentage points of the whole size.

On the other hand, joining 3 tables in a chain is much more expensive than a single join.

Saving CPU and query time calculations at the expense of a few more bytes (or kilobytes, or megabytes) is usually a good trade off.

Upvotes: 1

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