Choices, Choices - Loading and Modelling Slowly Changing Dimensions in the SQL Server 2008 Suite
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
Colin Hardie is a Senior BI Consultant with Information Management Group (IMGROUP), winners of the Microsoft Global Business Intelligence Partner of the Year award for the past four years. Previously Colin worked as a Technical Architect for a large pharmaceutical Information Services provider. Colin has worked with the SQL Server BI stack since 2001 and is a Microsoft Certified IT Professional Business Intelligence Developer. His main fields of expertise are SSIS and SSAS. Colin lives in London with his wife and two children.