Consider the following Relationship Entity Diagram (ERD). Which of the following possible relations will not hold if the above ERD is mapped into a relation model?
- A. Person (NID, Name)
- B. Qualification (NID, ExamID, QualifiedDate)
- C. Exam (ExamID, NID, ExamName)
- D. Exam (ExamID, ExamName)
Answer: C. Exam (ExamID, NID, ExamName)
Explanation: In the ERD, 'Exam' is an entity with ExamID and ExamName. The relationship 'Qualification' links Person and Exam. The NID should not be a foreign key in the 'Exam' table itself (unless it's 1:N and Exam is on the N side, but Qualification is M:N usually). The relation Qualification handles the link.