GO Classes 2023 | IIITH Mock Test 1 | Question: 46

Answer 1

Decomposition is lossy because $\text{XYUV}$ intersection $\text{YZUW} =\mathrm{YU}$ which is NOT a key in either $\text{P}$ or $\text{S}.$

In the decomposition, dependencies are preserved i.e. union of FD set of $\mathrm{P}, \mathrm{S}$ is equivalent to $\mathrm{F}$.

In $\mathrm{P}$, there is no non-prime attribute, so it is in $3 \mathrm{NF}$.

In $\mathrm{S}$, there is no non-prime attribute, so it is in $3 \mathrm{NF}$.

Comments

How are the FDs of P and S getting preserved?

Because I am not able to derive the FD V → W ?

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Get V→Y from P and Y→ W from S. You get the result as V→W.

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How are you able to get Y → W from S ???

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How you are getting V -> Y from P??? There is no such dependency.