Gate2018 cs Q65

0. Consider the following four relational schemas. For each schema, all non-trivial functional dependencies are listed. The underlined attributes are the respective primary keys.
Schema I : Registration (rollno, courses)
Field ‘courses’ is a set-valued attribute containing the set of courses a student has registered for.
rollno → courses
Schema II : Registration (rollno, courseid,
email)
Non-trivial functional dependencies:
rollno, courseid → email
email → rollno
Schema III : Registration (rollno, courseid,
marks, grade)
Non-trivial functional dependencies:
rollno, courseid → marks,
grade
marks → grade
Schema IV : Registration (rollno, courseid,
credit)
Non-trivial functional dependencies:
rollno, courseid → credit
courseid → credit
Which one of the relational schemas above is in 3NF but not in BCNF?

Answer
Comment
Array

Option : B
Explanation :
In Schema II : Registration (rollno, courseid,
email)
Non-trivial functional dependencies:
{ rollno, courseid → email
email → rollno }
candidate keys
{rollno, courseid,}
email courseid}
Given relation is in 3NF but not in BCNF.

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