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Explain in brief about critical column.A column (usually granular) is called as critical column which changes the values over a period of time.
For example, there is a customer by name ‘Anirudh’ who resided in Bangalore for 4 years and shifted to Pune. Being in Bangalore, he purchased Rs. 30 Lakhs worth of purchases. Now the change is the CITY in the data warehouse and the purchases now will shown in the city Pune only. This kind of process makes data warehouse inconsistent. In this example, the CITY is the critical column. Surrogate key can be used as a solution for this.Explain in brief about critical column.A critical column in a warehouse is a column whose value changes over a period of time. For e.g. city of the user. If a user resides in city 'abc' and the warehouse keeps a track of his per day expenses - when the user changes the city, the data warehouse becomes inconsistent since the city has changed and the expenses are shown under the new city.
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