Fourth Normal Form
------------------------------------

Students(RIN, Name, Email, Hobby, PhoneNumber)

RIN-> Name Email   x not in BCNF

Key: RIN, Hobby, PhoneNumber

Student can have multiple hobbies
Student can have multiple phones

BCNF Decomposition:

Students(RIN, Name, Email)   {RIN-> Name, Email}, Key: RIN, in BCNF

StudentInfo(RIN, Hobby, PhoneNumber)  {}, Key: all attributes, in BCNF

RIN    Hobby        PhoneNumber
1      Running      1234
1      Running      4567
1      Baking       1234
1      Baking       4567
2      Joomchi      3456
2      Joomchi      0954
2      Lampworking  0954
2      Lampworking  3456


Multi-valued attributes

RIN ->> Hobby
RIN ->> PhoneNumber

(RIN, Hobby)
(RIN, PhoneNumber)