DS0-001 Question #76: Real Exam Question with Answer & Explanation

Question

Which of the following NFs is considered the most preferable for relational database design?

Options

• A1 NF
• B3 NF
• C4 NF
• D2 NF

Explanation

3NF (Third Normal Form) strikes the ideal balance between eliminating data redundancy and maintaining practical query performance, making it the industry standard for relational database design. It removes transitive dependencies (non-key attributes depending on other non-key attributes) while keeping the schema straightforward to implement and maintain.

Why the distractors fall short:

• 1NF (A) only ensures atomic values and unique rows - it still allows partial and transitive dependencies, leaving significant redundancy.
• 2NF (D) goes further by eliminating partial dependencies, but transitive dependencies remain, so anomalies persist.
• 4NF (C) handles multi-valued dependencies and is technically "more normalized" than 3NF, but it's often over-engineering - the additional complexity rarely justifies the benefit in typical OLTP systems.

Memory tip: Think of normalization as a spectrum from "barely structured" (1NF) to "theoretically pure" (BCNF, 4NF, 5NF). 3NF is the "sweet spot" - it eliminates the most common real-world anomalies without sacrificing usability. On exams, "most preferable for relational design" almost always signals 3NF unless the question specifically mentions multi-valued dependencies (which points to 4NF).

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