4.5 3NF

Supplier(sno,sname,saddress)
Supp-part(sno,partno)
Cust-supp(partno,custid,quantity)
Part(partno,partdesc)
Cust(custid,custname,custaddr,sno) 

  sno -> sname,saddr
  partno -> partdesc
  partno,custid -> quantity
  sname -> sno
  custid -> custname,custaddr
  custid -> sno

The relations are now in 3NF.

Which of the following is true?

  1. The relations are not in BCNF.
     
  2. The relations are in BCNF. The dependency sname -> sno isn't a problem because sname is a candidate key (because it was stated that the supplier names are unique).
     
  3. The relations are in BCNF because there are no candidate keys other than the actual keys.
     
  4. The relations are not in BCNF because there are transitive dependencies.
     

Index