Slowly Changing Dimension Type 1: do not preserve any history versions of data. This methodology overwrites old data with new data, and therefore stores only the most current information. The number of records we store in SCD Type 1 do not increase exponentially as this methodology overwrites old data with new data Hence we may not need the performance improvement techniques.
Slowly Changing Dimension Type 2: also known SCD Type 2 is one of the most commonly used type of Dimension table in a Data Warehouse. SCD Type 2 dimension loads are considered to be complex mainly because of the data volume we process and because of the number of transformation we are using in the mapping.
Slowly Changing Dimension Type 3: preserves only few history versions of data, most of the time 'Current' and Previous' versions. The 'Previous' version value will be stored into the additional columns with in the same dimension record. In this article lets discuss the step by step implementation of SCD Type 3 using Informatica PowerCenter. The number of records we store in SCD Type 3 do not increase exponentially as we do not insert a record for each and every historical record. Hence we may not need the performance improvement techniques used in the SCD Type 2 Tutorial.