Which statement best describes the typical effect of denormalization on data redundancy?

• A. It eliminates duplicates
• B. It reduces redundancy
• C. It may introduce duplicate data
• D. It has no effect on redundancy

Answer: (C)

Denormalization is about trading some data integrity for faster reads by duplicating data across the design. When you denormalize, you keep copies of information in multiple places or store precomputed values so queries can be answered without expensive joins. That duplication is exactly what creates duplicate data, so the typical effect is that redundancy can be introduced. It isn’t about eliminating duplicates—normalization does that—and it does have an impact on redundancy, usually increasing it. This is a deliberate trade-off: you gain quicker access to data at the cost of more complex maintenance to keep all copies synchronized.