Alex Merced 2/19/2026

Slowly Changing Dimensions: Types 1-3 with Examples

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This technical article details the three most common Slowly Changing Dimension (SCD) patterns in data warehousing: Type 1 (Overwrite), Type 2 (Track Full History), and Type 3 (Track One Change). It explains why dimensions change, provides SQL examples for each type, and discusses the trade-offs between simplicity and historical accuracy to help choose the right design for analytics and reporting.

Slowly Changing Dimensions: Types 1-3 with Examples

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