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A table has columns: (student_id, student_name, course_name, instructor_name). What is wrong with this design?

medium📝 Debug Q6 of 15
SQL - Database Design and Normalization
A table has columns: (student_id, student_name, course_name, instructor_name). What is wrong with this design?
AIt is fully normalized
BIt causes data duplication and update anomalies
CIt uses foreign keys correctly
DIt has no primary key
Step-by-Step Solution
Solution:

  1. Step 1: Identify repeated data

    Course and instructor names repeat for many students causing duplication.

  2. Step 2: Recognize update anomaly risk

    Changing instructor name requires multiple updates, risking inconsistency.

  3. Final Answer:

    It causes data duplication and update anomalies -> Option B

  4. Quick Check:

    Repeated course data = duplication problem [OK]
Quick Trick: Repeated course info causes duplication and errors [OK]
Common Mistakes:
  • Assuming design is normalized
  • Ignoring update anomalies
  • Thinking missing primary key is main issue here

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