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