Functional Dependency

Question

{
(Eid, pno) --­­> hours,
Eid ­­--> Ename,
Pno ­­--> (Pname, Plocation),
Pname --­­> Plocation
}

in a relation R (Eid, Pno, hours, Ename, Pname, Plocation). After decomposition, the relation R1 (Pno, Pname, Plocation) is in __

1. BCNF
2. 3NF but not in BCNF
3. 1NF

Please answer with an explaination.

Comments

is it 1??

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That's what I thought too. But the answer seems to be 3.

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The key is {EID, Pno} together,

After decomposition the relation will be 

R1(Eid,Pno, Hours)

R2(Eid, Ename)

R3(Pno, Pname, Plocation)

R4(Pname, Plocation)

Decomosition is Lossless and Dependencies are preserved.

Then it should be In BCNF.

ANd Also R3(Pno, Pname, Plocation)

is also now in BCNF.

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@Shubhanshu

it is only in 2NF, not even in 3NF

for, R1 (Pno, Pname, Plocation), functional dependency acting are {Pno ­­-->(Pname, Plocation), Pname --­­> Plocation }

clearly only candidate key for R1 is Pno, now it is in 2NF(no partial dependecy) but not in 3NF because,

here in, Pname --­­> Plocation(nonkey--->non_prime) which is voilating 3NF.

Answer 1

anss