What is critical column?

Submitted by: Administrator
Let us take one ex: Suppose 'XYZ' is customer in Bangalore, he was residing in the city from the last 5 years, in the period of 5 years he has made purchases worth of 3 lacs. Now, he moved to 'HYD'. When you update the 'XYZ' city to 'HYD' in your Warehouse, all the purchases by him will show in city 'HYD' only. This makes warehouse inconsistent. Here CITY is the Critical Column. Solution is use Surrogate Key.
Submitted by: Administrator

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