SCD type 4 - Fast growing dimension

Writen by Devil 3:17 AM - 0 Comments

Fast growing dimension or SCD Type 4:

In slowly changing dimensions the dimension tables tend to grow slowly. Example: Location attribute of a customer changes very rarely. 

However the salary band of a customer is likely to change every year. These type of attributes causes the customer dimension table to grow rapidly and we need Fast Growing Dimension or SCD Type 4.

In SCD type 4 a junk dimension or a small dimension table with all the possible values of the rapid growing attributes of the dimension are maintained and a  dimension key of the new table should be maintained in the fact table. This way we can handle the rapid changes in the dimension table. 

Example : Dimension attributes of customer

C_Id
Name
Location
Age_band
Salary_band

The new tables are 

Table name : customer
C_Id
Name
Location

Table name: customer_mini
M_id
Age_band
Salary_band

Fact table:
Id
C_Id
M_Id
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