which of the following is in BCNF Form AND LOSSY OR LOSSLESS JOIN ? closed

Question

R(A,B,C,D)

1.  A->B , B->CD

2. A->B , B->C , C->D

3. AB->C , C->AD

4. A->BCD

1.  

Answer 1

1.  A->B , B->CD                   : CK : A  . It is in 2NF

2. A->B , B->C , C->D           : CK : A  . It is in 2NF

3. AB->C , C->AD                  : CK : AB  . It is in 2NF

4. A->BCD                              : CK : A  . It is in BCNF

Comments

https://gateoverflow.in/741/gate2001-2-23

CHECK ABOVE LINK

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THAT I LEARN  A RELATION IS DEPENDENCY PRESERVING IF

F1 U F2 U ...Fn=F

WHILE  FOR LOSSY

F1 ∩ F2 -> F1

OR F1 ∩  F2 ->F2 , WHERE F1 & F2 SHOULD BE CANDIDATE KEY .

IS IT RIGHT ?

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Hi,
the question you asked
and the above gate 2001-2-23 are different.
What i interpreted from your question is that FDs are given we have to check which is in BCNF.
the gate question is different
In options, the decomposed relations are provided and we have to find out which decomposition is in BCNF as well as lossless anf dependency preserving.