Consider the following functional dependencies in a database.
Date_of_Birth -> Age
The relation (Roll_number, Name, Date_of_birth, Age) is
in third normal form but not in BCNF
in none of the above
There are three FDs that are valid from the above set of FDs for the given relation :
Name -> Roll_number
Roll_number -> Name
candidate keys for the above are : (Date_of_Birth,Name) and (Date_of_Birth,Roll_number)
clearly there is partial dependency here (Date_of_Birth -> Age) and Age is not a prime attribute. So it is only in 1NF.