Page 145 - DCAP402_DCAO204_DATABASE MANAGEMENT SYSTEM_MANAGING DATABASE

Database Management Systems/Managing Database

Notes Table before Boyce Codd Normal Form
Loan Info Table

Branch Name Customer Name Loan Name Amount
Delhi Ajay L-101 10,000
Vizag Ram L-230 15,000
Delhi Sonali L-101 10,000
Mumbai Jagadish L-420 1,00,000
Trivandum Usha L-500 5,000
Mysore Pradeep L-784 12,000

Table after Boyce Codd Normal Form

Borrower Table

Customer Name Loan Name
Ajay L-101
Ram L-230
Sonali L-101
Jagadish L-420
Usha L-500
Pradeep L-784

Loan Table

Branch Name Loan Name Amount
Delhi L-101 10,000
Vizag L-230 15,000
Delhi L-101 10,000
Mumbai L-420 1,00,000
Trivandum L-500 5,000
Mysore L-784 12,000

3NF – BCNF Comparison

When a relation has more than one candidate key, data maintenance anomalies may result even
though that relation is in 3NF.

Example: Consider the Student_Advisor relation as shown below:
Relation in 3NF but not BCNF STUDENT ADVISOR

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