#madenotes

Question

---

A	B	C
1	1	1
1	1	0
2	3	2
2	3	2

FIND NON-TRIVIAL DEPENDENCY

Answer 1

Trivial refers to implicit dependency ..so A->A , B->B,C->C are trivial Dependency..

Now for Non-Trivial dependency ...say we have M->N then for every tuple of M if we have same value in N then we can say it as non trivial .

So from the given table we can say...C->A , C->B , B->A , A->B , AC -> B  , BC-> A these are NON-Trivial Dependency as

(Consider the case of C->A) for every Tuple in C we have same value for it Tuple A .

Comments

$BC \rightarrow A $ is also present.

---

Also include  this in your answer.

$BC\rightarrow A$

---

AB <- C also present

---

C -> AB will also be.

Answer 2

The non-trivial dependencies would be:

$A\rightarrow B$

$B\rightarrow A$

$C\rightarrow AB$

$AC\rightarrow B$

$BC\rightarrow A$

Comments

C$\rightarrow$A,C$\rightarrow$B also persent

---

Bro, C→AB is can be expressed as $C\rightarrow A$ and $C\rightarrow B$. You can express either way.

 

 

Answer 3

We get the following minimal set of FD’s.

A->B,B->A,C->A,C->B