How do you manage slowly changing dimensions? What are the fields requ

1.	How do you manage slowly changing dimensions? What are the fields required in managing different types if SCD?
Answer» SCD Type 1 No history preservation Natural consequence of normalization SCD Type 2 Preserving all history and new rows There are new rows generated for significant changes You need to use of a unique key There are new fields are generated to store history data You need to manage an Effective_Date field. SCD Type 3 Limited history preservation In this only two states of data are preserved - current and old

How do you manage slowly changing dimensions? What are the fields required in managing different types if SCD?

Answer»

SCD Type 1 No history preservation

Natural consequence of normalization

SCD Type 2 Preserving all history and new rows

There are new rows generated for significant changes

You need to use of a unique key

There are new fields are generated to store history data

You need to manage an Effective_Date field.

SCD Type 3 Limited history preservation

In this only two states of data are preserved - current and old