[From SQL Server Performance
Having discussed type1 slowly changing dimensions (SCD) in Part 1 of this article, this article will talk about further on SCDs and how we can implement them in SQL Server 2005.
What is Type2 SCD
A Type 2 SCD writes a record with the new attribute information and preserves a record of the old dimensional data. Implementing type2 changes within a data warehouse environment might require significant analysis and development time. These changes accurately partition history across time more efficiently than other types. However, they also add new records to the data warehouse environment thus, significantly adding to the database size.
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