Keep track of your data by Slowly Changing Dimensions
Data related dimensions changes over time are known as Slowly Changing Dimensions. The data in the dimensions may change according to the time, the attributes in the dimension table also changes. We can overwrite the existing values with the new values and also can store the existing data.In order to track the records, there are three categories to solve this issue that commonly occurs in Data Warehousing environment.
For Example: Price of a Product may change over time
Names of people, country and state names may change over time.
Slowly Changing Dimensions are categorized into three types named as Type 1, Type 2 and Type 3.
SCD Type 1: New data replaces the original data in the dimensions table. There won’t be any trace of the old records existing.
SCD Type 2: New data is added to the dimensions table, both the new and existing data is recorded.
SCD Type 3: Existing data will be modified and the changes are reflected in the dimensions table.