Data anomalies: In some poorly designed tables, changes to data cause undesirable side effects. What are these consequences commonly called in normalization theory?
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Areferential integrity constraints.
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Bmodification anomalies.
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Cnormal forms.
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Dtransitive dependencies.
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Ecascading actions.
Answer
Correct Answer: modification anomalies.
Explanation
Introduction / Context:Normalization aims to reduce redundancy and prevent problematic side effects when inserting, updating, or deleting data. Recognizing anomalies helps justify decomposition into higher normal forms.
Given Data / Assumptions:
- Anomalies arise from redundancy and inappropriate attribute grouping.
- Types include insertion, update, and deletion anomalies.
- We assume standard relational definitions.
Concept / Approach:“Modification anomalies” is the umbrella term for unwanted effects caused by data modifications in non-normalized designs. They reflect design flaws that normalization (1NF, 2NF, 3NF, BCNF) tries to address.
Step-by-Step Solution:
Identify symptom: odd side effects when changing data.Classify as insertion/update/deletion anomalies.Conclude: These are modification anomalies.Verification / Alternative check:Normalization literature uses the term “modification anomalies” extensively as the motivation for decomposing relations.
Why Other Options Are Wrong:Referential integrity constraints: Rules that prevent orphaned references, not the anomalies themselves. Normal forms: Targets/criteria to prevent anomalies. Transitive dependencies: A specific dependency type that can cause anomalies but is not the name of the consequence.
Common Pitfalls:Confusing the cause (dependencies) or cure (normal forms) with the symptom (anomalies).
Final Answer:modification anomalies.