What is an advantage of Type 1 slowly changing dimension?

• A. keeps history by adding new rows
• B. with no historical data, maintenance is easy and data warehouse size is reduced
• C. ensures constant freshness
• D. data warehouse size is increased

Answer: (B)

Type 1 slowly changing dimension overwrites the existing value with the new one, so historical versions are not kept. The practical advantage of this approach is that maintenance is straightforward and storage is minimized, because you only store the current state for each key and don’t manage multiple rows representing past values. The trade-off is you lose the ability to see how a value changed over time. This is why the option describing no historical data leading to easier maintenance and a smaller warehouse is the best fit. A choice about keeping history by inserting new rows would describe a Type 2 approach, not Type 1, and statements about constant freshness or increased size don’t align with Type 1’s behavior.