Question

For a binary many to many relationship, the ________ of the participating entity sets becomes the prime attribute

(a) Intersection of primary keys

(b) Primary key of either one

(c) Union of primary keys

(d) Primary key on the many side

The question was asked in an international level competition.

I'm obligated to ask this question of Reduction to Relational Schema topic in division Database Design and the ER Model of RDBMS

Answer 1

The correct option is (d) Primary key on the many side

For explanation I would say: For a binary many to many relationship, the primary key on the many side of the participating entity sets becomes the prime attribute.