Answer
Normalization reduces redundancy through well-structured relations, while denormalization deliberately adds redundancy. • Normalization usually simplifies integrity rules. • Denormalization may improve a measured read path. • Choose using correctness requirements and workload evidence rather than habit.
💡 SQL Example
SELECT o.order_id, COUNT(oi.item_id) FROM orders o JOIN order_items oi ON oi.order_id = o.order_id GROUP BY o.order_id;
Result
Normalized data calculated through a join
⚡ Quick Revision
Normalize for clear integrity; denormalize only for a proven tradeoff.