BitWithBite
SQL Worksheet
🗃 Normalization 1NF 2NF 3NF
SCORE___ / 20
NameClassDate
After this worksheet you can
Apply 1NF atomic values2NF full key dependence3NF no transitive depsRecognise redundancy🧠 Section A · Concept Check ● BEGINNER 4 × 1 = 4
11NF forbids:
22NF concerns:
33NF removes:
4Normalization mainly reduces:
🧮 Section B · Problem Solving ● INTERMEDIATE 2 + 3×3 = 11
51NF: every cell holds one value.
6Update anomalies happen with data.
7Fix 1NF: phone column contains '0301, 0302'.
8Spot the 3NF issue: orders(id, customer_id, customer_city).
9What anomaly happens updating a duplicated address?
🚀 Section C · Challenge ● CHALLENGE 5
10Why might a data warehouse denormalize?
💭 Reflection — the most useful thing I learned:
A ___/4 B ___/11 C ___/5 Total ___/20
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✂ answer key — fold or cut before handing out
1-A 2-A 3-A 4-A | 5 atomic 6 redundant/duplicated 7 = Move phones to a phones(user_id, phone) table - one per row 8 = customer_city depends on customer, not the order - move it to customers 9 = Update anomaly - some copies get missed and disagree | 10 = Fewer joins = faster analytical reads