The Art of Simplicity0 Hot9 phút
Slowly Changing Dimensions – An introduction
A practical introduction to Slowly Changing Dimensions (SCD) for those new to data warehousing. Covers the core fact/dimension table split and explains all four SCD types: Type 0 (fixed attributes), Type 1 (overwrite), Type 2 (full history with surrogate keys and effective dates), Type 3 (previous value only), and Type 4 (separate current and history tables). Includes a decision framework for choosing the right type based on business needs rather than technical defaults, and notes that different columns in the same table can use different SCD types.