Slowly Changing Dimensions (SCDs) in their various forms are a standard part of most BI implementations and yet they still manage to confound many developers when they come to implement them. Drawing from experience gained in the field, this session will briefly describe what an SCD is, what it does, how it can best be modelled in both the relational and OLAP layers and which of the various options available in SQL Server 2008 is the best way of loading it. Topics covered may include: - "There are 6 types of SCD? WHAT?!?"; - "To Snowflake or not to Snowflake?"; - "The SCD Wizard is brilliant and should always be used"; * - "CHECKSUM(): the solution to all my problems"; * - "MERGE - the obligatory SQL Server 2008 bit": It may also try and present an adaptable and performant strategy for loading SCDs that actually works. * - May not be true
Presented by Colin Hardie at SQLBits III