Dimensional modeling uses surrogate keys mainly to achieve what?

• A. Enforcing unique constraints on every row
• B. Stability of keys regardless of changes to natural keys
• C. Sorting dimension data efficiently
• D. Replacing all primary keys in the warehouse

Answer: (B)

The main idea is to keep references in the warehouse stable and decoupled from the source systems. Surrogate keys are artificial identifiers assigned to each dimension row, separate from the business or natural keys used in source data. This means that even if a natural key changes in the source (like a customer id, product code, or location key), the link between facts and dimensions stays intact because the warehouse uses the surrogate key for joins. It also enables proper history tracking: when a dimension attribute changes, you can add a new row with a new surrogate key (while the old row remains for historical analysis), preserving accuracy without touching existing fact records. Because surrogate keys are typically simple integers, joins are fast and the design remains stable even as source keys evolve.