Difficulty: Easy
Correct Answer: Applies — in most cases anomalies justify BCNF or near-BCNF
Explanation:
Introduction / Context:
Modification anomalies occur when redundant storage causes inconsistent updates, prevents valid inserts, or deletes unintended information. BCNF eliminates many root causes. This question asks whether anomalies are generally severe enough to warrant BCNF in typical operational schemas.
Given Data / Assumptions:
Concept / Approach:
BCNF offers strong guarantees against dependency-driven redundancy. Most OLTP tables benefit from BCNF or 3NF with careful exceptions. Where denormalization is chosen, compensating controls are essential.
Step-by-Step Solution:
Analyze functional dependencies for each table.Decompose to BCNF or 3NF where anomalies exist.Measure query and write performance.If denormalizing, document fields duplicated and define authoritative sources.Enforce constraints, triggers, or ETL rules to maintain consistency.
Verification / Alternative check:
Audit for conflicting values and orphaned facts; fewer inconsistencies post-normalization indicate success.
Why Other Options Are Wrong:
Claiming anomalies are rare contradicts operational experience. Limiting BCNF to audit tables or composite keys misunderstands its scope.
Common Pitfalls:
Over-normalizing without regard to critical query paths; denormalizing without governance, leading to drift.
Final Answer:
Applies — in most cases anomalies justify BCNF or near-BCNF
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