Consider relation schema RA- B- C- D and the two sets of fucntional dependencies -H - A - B- B- A- AB - C- AC - D- B- CG - CA - B- BA - D- B - D- DB - CWhich of the following is true -

Check G covers H: 1. A → B cannot be derived from G which is present in H, So G not covers H nbsp;Check H covers G 1. CA → B can be derived from H i ...

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Consider rela...

Question

Consider relation schema R(A, B, C, D) and the two sets of fucntional dependencies :

$H = {A \to B, B \to A, A B \to C, A C \to D, B \to C}$
$G = {C A \to B, B A \to D, B \to D, D B \to C}$

Which of the following is true ?

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Solution

Check G covers H:
$1. A \to B cannot be derived from G which is present in H, S o G n o t c o v e r s H$

Check H covers G
$1. C A \to B can be derived from H i.e. A \to B t h e n C A \to C B$ .

$2. B A \to D can be derived from H i.e A \to B, B \to A C . A C \to D t h e n B \to D a n d A B$

$3 B \to D can be derived from H i.e. A \to B, B \to A C, A C \to D t h e n B \to D .$
$4. D B \to C can be derived from H i.e. B \to C t h e n D B \to D C .$
Hence H covers G

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Consider relation schema R(A, B, C, D) and the two sets of fucntional dependencies : H={A→B, B→A, AB→C, AC→D, B→C} G={CA→B, BA→D, B→D, DB→C} Which of the following is true ?

Consider relation schema R(A, B, C, D) and the two sets of fucntional dependencies :

$H = {A \to B, B \to A, A B \to C, A C \to D, B \to C}$
$G = {C A \to B, B A \to D, B \to D, D B \to C}$

Which of the following is true ?