491 views
0 votes
0 votes

Consider the following relation, R(A,B,C) and the following functional dependencies FD={ A→B, B→C, C→A }.

Consider the following statements

Statement I: The following relation is in BCNF, as A,B and C are key.

Statement II: A prime attribute cannot be transitively dependent on a key in BCNF relation, and we have { A (key) → B and B→ C (Prime Attribute) }, so the given relation is not in BCNF.

  1. Statement I and II both are correct.
  2. None of statement I and II is correct
  3. Only statement II is correct.
  4. Only statement I is correct.

1 Answer

Best answer
2 votes
2 votes

Answer: D
 

Statement I is quite obvious, it is true.

Statement II:
According to Navathe, transitive dependency is defined as follows



Now here $Z$ can neither be candidate key nor a subset of any key (set of prime attributes), this means $Z$ must be a non-prime attribute, so BCNF cannot have transitive dependency since LHS of every dependency must be a superkey. So BCNF cannot have transitive dependency.
Hence, statement II is incorrect.

selected by

Related questions

1 votes
1 votes
2 answers
1
aditi19 asked Apr 14, 2019
1,844 views
Decompose into BCNFR(A, B, C, D, E)FD: AB->C, C->D, D>B, D->E
2 votes
2 votes
1 answer
2
Na462 asked Jul 14, 2018
1,856 views
0 votes
0 votes
2 answers
4