Register

GO Classes DPP | Databases | Functional dependency | JMU

522 views
5 5 votes
Consider a relation R(A, B, C, D, E, F, G, H, I, J) with functional dependencies:

$$
\mathrm{AB} \rightarrow \mathrm{C}, \mathrm{BD} \rightarrow \mathrm{EF}, \mathrm{AD} \rightarrow \mathrm{GH}, \mathrm{~A} \rightarrow \mathrm{I}, \mathrm{H} \rightarrow \mathrm{~J} .
$$

Which of the following is a candidate key for R ?
A) $A B D$
B) $A B D H$
C) $A D$
D) $A B D I$

3 Answers

2 2 votes
$\mathrm{ABD}^{+}=\{\mathrm{A}, \mathrm{B}, \mathrm{C}, \mathrm{D}, \mathrm{E}, \mathrm{F}, \mathrm{G}, \mathrm{H}, \mathrm{I}, \mathrm{J}\} \Rightarrow$ all attributes covered.
• reshown by
0 0 votes
ABD+ = {A,B,D}

           = {A,B,D,C,E,F,G,H}    Since AB => C and BD => EF and AD => GH

           = {A,B,D,C,E,F,G,H,I,J}    Since H => J and A=>I

So ABD is a candidate key Option A is True.
0 0 votes

A,B,D are not present Right hand side of any of the function dependency that means ABD is must be part of CK and as we know that if ABD itself is the candidate key that's means adding something to it will make it sk not candidate key and if you are going to remove somthing from ABD then it will not become ck 

Voting & Accepting an answer helps improve the community
Answer:
← Previous · GO Classes DPP | Dat...Next → · GO Classes DPP | Dat...
← Previous in category · GO Classes DPP | Dat...Next in category → · GO Classes DPP | Dat...
Position:
Show:

Related questions

10 10 votes
5 5 answers
763
763 views
GO Classes asked Jul 20, 2025
763 views
GO Classes DPP | Databases | Functional dependency | NIELIT
Which functional dependency holds in given relation $\mathrm{R}(\mathrm{A}, \mathrm{B}, \mathrm{C})$ and why? $$\begin{array}{|c|c|c|}\hline \mathbf{A} & \mathbf{B} & \m...
3 3 votes
6 6 answers
711
711 views
GO Classes asked Jul 11, 2025
711 views
GO Classes DPP | Databases | Functional dependency | JMU
Consider a relation $\mathbf{R(A, B, C, D, E)}$ with the functional dependencies:$$\mathbf{CE} \rightarrow \mathbf{D}, \mathbf{D} \rightarrow \mathbf{~B}, \mathbf{C} \rig...
2 2 votes
5 5 answers
673
673 views
GO Classes asked Jul 11, 2025
673 views
GO Classes DPP | Databases | Functional dependency | JMU
What is the highest normal form satisfied by the relation $R(A, B, C, D, E)$ with functional dependencies $\mathbf{C E} \rightarrow$ $\mathbf{D}, \mathbf{D} \rightarrow \...
2 2 votes
3 3 answers
598
598 views
GO Classes asked Jul 20, 2025
598 views
GO Classes DPP | Databases | B tree | ISRO
If a node has $K$ children in $B$ tree, then the node contains exactly_______keys.$K^2$ $K-1$ $K+1$ $\sqrt{K}$