Slowly Changing Dimensions ( SCD Type I/II/III )

Slowly Changing Dimensions (SCD’s)

SCD is a dimension which captures the changes that occur over a period of time.

• Type I – Contains only current data. Change in source is overwritten
• Type II-Maintains complete history + Current data
• Type III-Partial (recent) history + Current data

In OLTP

In DWH

• Active record is where end date is null
• History
• Active status(Active record – Max Version)
• Change No (Version)
• Duration (Time stamp)