1 votes 1 votes Databases databases database-normalization + – ankitgupta.1729 asked Dec 16, 2017 • retagged May 27, 2021 by Shiva Sagar Rao ankitgupta.1729 1.1k views answer comment Share Follow See all 14 Comments See all 14 14 Comments reply srestha commented Dec 16, 2017 reply Follow Share no one is false all are true 0 votes 0 votes ankitgupta.1729 commented Dec 17, 2017 reply Follow Share Given answer is :- (3) and (4) are false 0 votes 0 votes Ashwin Kulkarni commented Dec 17, 2017 reply Follow Share Okay I have answered which are true initially :p I hided that comment. Anyways 3 & 4 are false 3 )Transitive dependecy is already removed in 3NF hence it cannot sustain in BCNF. 4) What is intrasitivity ? IF A->B and B->C then A->C should be false. But in 3NF, either LHS is Key or RHS is PA. Hence anyhow Key and PA will be transitively dependet. eg. AB is key. AB->C C->A hence AB->A trivial transitive dependecy. 2 votes 2 votes ankitgupta.1729 commented Dec 17, 2017 reply Follow Share OK got it.. Thanks.. 0 votes 0 votes srestha commented Dec 17, 2017 reply Follow Share @Ashwin 3NF removed the transitive dependendecy for nonkey-> nonkey not for nonkey->prime or prime->prime right? where am I wrong? 1 votes 1 votes Manu Thakur commented Dec 17, 2017 reply Follow Share https://gateoverflow.in/1260/gate2007-62-ugcnet-june2014-ii-47 0 votes 0 votes Manu Thakur commented Dec 17, 2017 reply Follow Share @srestha can you please explain why is 4th statement true? even i am not getting the meaning of "intransitively'. 0 votes 0 votes Anu007 commented Dec 17, 2017 reply Follow Share Statement -3: R(A,B,C,D) With ABC-> D , D-> A .........So False. Statement -4; R(A,B,C,D) With AB-> D , C-> A ........So False. 0 votes 0 votes Manu Thakur commented Dec 17, 2017 reply Follow Share @anu can you explain what exactly is the meaning of 4th statement, specially the word "intransitively". 0 votes 0 votes Anu007 commented Dec 17, 2017 reply Follow Share i took as not transitive. 0 votes 0 votes Manu Thakur commented Dec 17, 2017 reply Follow Share not transitive means A->B ( non transitive dependency) A->B, B->C, then A->C is transitive dependency is it? it's from some test series, i think. 0 votes 0 votes srestha commented Dec 18, 2017 reply Follow Share yes intrasitive means not transitive , I too think so. 3)"A prime attribute can transitively dependent on key of BCNF" R(A,B,C,D) With ABC-> D , D-> A what is key here (ABC),(DBC), So, this should be true It will be true if "A prime attribute must transitively dependent on key of BCNF" or "A prime attribute can transitively dependent on nonkey of BCNF" ---------------------------------------------------------------------------------------------------------------- 4)"A prime attribute can intransitively dependent on key in 3NF relation" R(A,B,C,D) With AB-> C here C is prime attribute, which intransitively dependent on key. if atleast one example satisfies, we can say ------------------------------------------------------------------------------------------- tell me where am I wrong? 0 votes 0 votes vamp_vaibhav commented Dec 18, 2017 reply Follow Share Srestha.. In your example how C becomes prime attribute and AB is key.?? . I think another counter example would be good 0 votes 0 votes srestha commented Dec 18, 2017 reply Follow Share ok AB->C, BD->A now correct? 0 votes 0 votes Please log in or register to add a comment.
2 votes 2 votes statement 1 and 2 both are true abhishekmehta4u answered Mar 24, 2018 abhishekmehta4u comment Share Follow See 1 comment See all 1 1 comment reply BASANT KUMAR commented Sep 18, 2018 reply Follow Share your (2) example will be in 3 NF c.k=A,B,C A->B B->C C->A in L.h.s all of them is c.k so it will be in 3nf as well as BCNF . 0 votes 0 votes Please log in or register to add a comment.