Under normal circumstances, the cardinality ratio of the binary relationship…
2017
Under normal circumstances, the cardinality ratio of the binary relationship “Write” relating “Author” and “Book” entities is:
- A.
1 : N
- B.
N : 1
- C.
1 : 1
- D.
M : N
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Correct answer: D
Under normal circumstances, one author can write multiple books, and a single book can be co-authored by multiple individuals. This creates a bidirectional multi-valued mapping between the two entities. Therefore, the cardinality ratio is Many-to-Many (M : N). Option D is correct.