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For a database relation $R(a, b, c, d)$, where the domains $a, b, c, d$ include only atomic values, only the following functional dependencies and those that can be inferred from them hold

  • $a \rightarrow c$
  • $b \rightarrow d$

This relation is

  1. in first normal form but not in second normal form

  2. in second normal form but not in first normal form

  3. in third normal form

  4. none of the above

asked in Databases by (66.1k points)   | 990 views

2 Answers

+17 votes
Best answer
Ck is ab.

Since all a,b,c,d are atomic so the relation is in 1 NF.

Now check the FD s.

a->c(P->NP)

b->d(P->NP)

Since there are partial dependencies,so it is not 2 NF.

a}Ans 1NF but not 2NF
answered by (3.6k points)  
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by using decomposition in ac bd ab

 sonam vyas

 

by using decomposition in ac bd ab

 what is means?

i have a doubt

assume AB is a primary key  and relation (ABCDE)

dependency:

1)A---->BCDE

2)AB---->CDE

3)AB----->BDE

for 1 & 3,is partial dependency exist ?
@bikram sir see this pls
AB is key

Prime attribute ={A,B}

For partial FD : prime attribute -> non prime

1) is partiall FD

2) and 3) are not partial FDs

 Gate Ranker18

 

see 

for 3,AB---->B(KEY---->PRIME ATTRIBUTE)ALLOWED IN 2NF

AB---->DE NO PARTIAL DEPENDENCY

+3 votes
Answer: A

ab is the candidate key.
answered by (35.4k points)  

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