Slowly Changing Dimensions in SQL Server 2005

IntroductionSlowly changing dimensions (SCD) are very useful in data warehouses. Even though they are useful, it is very difficult to implement slowly changing dimensions with most of ETL tools. In case of SQL Server 2000 it was difficult to implement SCD's as there was no direct way of implimenting them. As you are aware there were numerous changes in SQL Server 2005 including the introduction of a SCD data flow task. This article explores the options available in the SQL Server 2005 for SCD's.RequirementsYou need to have installed SQL Server 2005 with Business Intelligence Development Studio (BIDS). It will also be beneficial if you know how to create simple SQL Server Integration Services (SSIS) packages. However, as usual I will elaborate on how to develop them when and where ever possible. What is SCD?The "Slowly Changing Dimension" problem is a common one particular to data warehousing. In a nutshell, this applies to cases where the attribute for a record varies over time. Let us take this hypothetical example. Let us say that we have a fact table that contains customersk.