Which of the following statements best describes the main reasons for…
2017
Which of the following statements best describes the main reasons for normalizing relational database? ( I ) To achieve physical data independence. ( II ) To remove data anomalies (insertion, update, deletion anomalies). ( III ) To save space on disk.
- A.
(I), (II) and (III)
- B.
(I) and (II) only
- C.
(I) and (III) only
- D.
(II) and (III) only
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Correct answer: D
Answer: Statements II and III are correct; Statement I is not.
Why statement I is incorrect: Physical data independence refers to the DBMS architecture (separation between internal and conceptual schemas). It is not achieved by the normalization process itself.
Why statement II is correct: Normalization reorganizes relations to remove redundancy and to ensure functional dependencies are properly represented. This removes insertion, update, and deletion anomalies and improves data consistency.
About statement III: Normalization reduces redundant storage which can lead to disk-space savings. However, this is generally a secondary benefit rather than the primary design goal. In some cases normalization can add overhead (more tables, keys, or indexes), so space savings are not guaranteed.
Conclusion: The best choice is the combination that includes removing data anomalies (the primary purpose) and the reduction of redundancy (a common secondary benefit): statements II and III.