ITPEC FE Subject A October 2025 Question 19

Transitive Functional Dependency — identify a valid A → B → C chain from given FDs.

Transitive FD means: if A → B and B → C both hold as direct FDs, then A → C is a transitive dependency through B.

Given functional dependencies:
- {OrderCode, ProductCode} → {CustomerOrderQuantity, OrderAmount}
- OrderCode → {OrderDate, CustomerCode, OrderManagerCode}
- ProductCode → {ProductName, SupplierCode, ProductSalePrice}
- SupplierCode → {SupplierName, SupplierAddress, SupplierManagerCode}
- CustomerCode → {CustomerName, CustomerAddress}

Check each option:

• •(a) OrderCode → CustomerCode → CustomerAddress ✅
• •OrderCode → CustomerCode — from FD #2
• •CustomerCode → CustomerAddress — from FD #5
• •Both steps are valid direct FDs → transitive dependency holds

• •(b) OrderCode → ProductCode → CustomerOrderQuantity ❌
• •OrderCode → ProductCode does not exist (ProductCode is part of a composite key, not determined by OrderCode alone)

• •(c) ProductCode → SupplierCode → ProductSalePrice ❌
• •SupplierCode → ProductSalePrice does not hold — ProductSalePrice depends on ProductCode, not SupplierCode

• •(d) SupplierCode → SupplierManagerCode → SupplierAddress ❌
• •SupplierManagerCode → SupplierAddress does not hold — SupplierAddress depends on SupplierCode, not SupplierManagerCode

Key rule: For a transitive FD A → B → C, both A → B and B → C must be independently valid functional dependencies in the given set.

AI-generated — may contain errors