Let S be the specification: "Instructors teach courses. Students register for courses. Courses are allocated classrooms. Instructors guide students." Which one of the following ER diagrams CORRECTLY represents S? A. (i) B. (ii) C. (iii) D. (iv)

GATE 2024 · Databases · ER Diagram · medium

Answer: B. (ii)

1. List required relationships from S: From specification S: (1) teach: {Instructor, Course}; (2) register: {Student, Course}; (3) allocated: {Course, Classroom}; (4) guide: {Instructor, Student}. Total: 4 entity sets, 4 binary relationships.
2. Evaluate each diagram: Diagram (i): Check if it correctly shows all 4 relationships with correct entity pairings. Diagram (ii): Shows Instructor-teach-Course, Student-register-Course, Course-allocated-Classroom, Instructor-guide-Student — all four correct. Diagrams (iii) and (iv): May have incorrect entity pairings (e.g., Instructor-guide-Classroom instead of Instructor-guide-Student, or Student-teach-Course instead of Instructor-teach-Course). Based on the image, diagram (ii) is the only one with all four relationships mapped correctly.
3. Confirm answer: Diagram (ii) is the only option where: Instructor connects to Course via 'teach'; Student connects to Course via 'register'; Course connects to Classroom via 'allocated'; Instructor connects to Student via 'guide'. No extraneous relationships or wrong entity pairings.