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Recent questions tagged bcnf-decomposition

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DBMS made easy test series - bcnf decomposition
$(A)1$ $(B)2$ $(C)4\\$ $(D)\ 5$

tirth_patel asked in Databases Jan 17, 2022

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1 answer

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GeeksForGeeks AIM 2 - BCNF - databases
How many minimum relations are required for the following Relation R(A, B, C, D, E) with FD {A → BC, CD → E, B → D, E → A} to convert into BCNF without violation of lossless and dependency preserving decomposition _________.

atulcse asked in Databases Jan 15, 2022

379 views

1 vote

2 answers

3

NIELIT 2016 DEC Scientist B (IT) - Section B: 44
Which one of the following statements about normal forms is FALSE? BCNF is stricter than $3$NF. Lossless, dependency-preserving decomposition into BCNF is always possible. Lossless, dependency-preserving decomposition into $3$NF is always possible. Any relation with two attributes is BCNF.

Lakshman Patel RJIT asked in Databases Mar 31, 2020

by Lakshman Patel RJIT

1.1k views

4 votes

5 answers

4

NIELIT 2017 DEC Scientist B - Section B: 1
Which one of the following statements are not correct? $S1$: $3$NF decomposition is always lossless join and dependency preserving. $S2$: $3$NF decomposition is always lossless join but may or may not be dependency preserving. $S3$: BCNF decomposition is always ... may not be dependency preserving. Only $S1$ Only $S4$ Both $S1$ and $S4$ Both $S2$ and $S3$

Lakshman Patel RJIT asked in Databases Mar 30, 2020

by Lakshman Patel RJIT

2.5k views

1 vote

3 answers

5

ACE Test Series : dependency preserving
R(A,B,C) is a relation.Which of the following don't have dependency preserving BCNF decomposition? A->B, B->C A->B,B->C,C->A AB->C,C->A None of these

ushamya asked in Databases Jun 3, 2019

693 views

1 vote

2 answers

6

Molina Exercise-3.3 BCNF decomposition
Decompose into BCNF R(A, B, C, D, E) FD: AB->C, C->D, D>B, D->E

aditi19 asked in Databases Apr 14, 2019

1.3k views

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0 answers

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self doubt - NO. of tables after normalizing
Are 3NF decompostions and BCNF decompostions unique? Are 4NF important for GATE (since I've left them :( ) See, I am asking this question because I want to know whether they'll ask about no. of tables we get after normalizing upto 3nf or bcnf. Now ... I am in a bit hurry to search for that.. so please forgive me if it has been already asked.) Thank you.

Harsh Kumar asked in Databases Jan 21, 2019

253 views

0 votes

0 answers

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GA_Testseries
is this in 3NF?

aditi19 asked in Databases Dec 10, 2018

404 views

2 votes

1 answer

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aditi19 asked in Databases Dec 10, 2018

324 views

3 votes

1 answer

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Raghuramkrishnan
R(A, B, C, D) FD: B->C, D->A is the following decomposition in BCNF? R1(B, C), R2(A, D), R3(C, D)

aditi19 asked in Databases Nov 29, 2018

742 views

2 votes

1 answer

11

BCNF Decomposition

Na462 asked in Databases Jul 14, 2018

by Na462

1.3k views

2 votes

2 answers

12

Function Dependency question
Consider a relation R(A,B,C,D,E,F,H) with A as the only key. Assume that the dependencies E->F and C-> DEH hold.on R. 1. Is R in 2NF? If not, decompose to 2NF. 2. is R in 3NF? if not, decompose to 3NF. //What does " with A as the only key" mean ?

karthikmenon asked in Databases Jun 23, 2018

by karthikmenon

697 views

2 votes

2 answers

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NORMALIZATION
Given: The Relation R(A,B,C,D,E) having (A,B) as Primary key. The set of functional dependencies: (A,C)-->D , (B,D)-->E. I want to Know whether the functional dependencies Given above are Partial FD's or Not?

pradeepchaudhary asked in Databases Jun 8, 2018

by pradeepchaudhary

1.2k views

2 votes

1 answer

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Mk Utkarsh asked in Databases Jan 12, 2018

1.0k views

2 votes

1 answer

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Question
I am getting 3 tables as R1(ABD) , R2(CE) and R3(AC). Is it correct?

AnilGoudar asked in Databases Jan 10, 2018

263 views

0 votes

1 answer

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Normalization
Please explain with example how lossless decomposition into BCNF is possible but dependency preservating BCNF decomposition may not be possible for all relations?

Mk Utkarsh asked in Databases Nov 24, 2017

377 views

0 votes

0 answers

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Question regarding BCNF Normalization
I came across a statement that says that in BCNF, a prime attribute cannot be transitively dependent on a key. But consider a relation R (A, B, C) where, A --> ABC , B --> ABC , C --> ABC Clearly it is in BCNF and each of A ... > C . Thus, we can tell C(a prime attribute) is transitively dependent on A (a candidate key) !! Where am I making mistake?

humblefool asked in Databases Nov 8, 2017

200 views

6 votes

2 answers

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Ace Test Series: Databases - Database Normalization

Shivansh Gupta asked in Databases Oct 2, 2017

by Shivansh Gupta

772 views

2 votes

2 answers

19

Lossless decomposition
Relation: R(ABCDE): FDs: A->BC, CD->E, B->D, E->A This relation is not in BCNF bcz of FD B->D. So how it make BCNF by decomposition so that the resultant decomposition is both lossless and dependency preserving ? plzz explain ?

rishu_darkshadow asked in Databases Sep 20, 2017

by rishu_darkshadow

2.7k views

1 vote

1 answer

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nitish asked in Databases Aug 4, 2017

by nitish

230 views

1 vote

2 answers

21

BCNF-decomposition
Consider the following relation: R (ABCDEF) F = {AB → C, BC → A, AC → B, B → D, C → E} The minimum number of relations required which satisfy BCNF, lossless join decomposition and dependency preserving decomposition are

reena_kandari asked in Databases Feb 1, 2017

by reena_kandari

391 views

1 vote

2 answers

22

BCNF Decomposition

rahul sharma 5 asked in Databases Jan 8, 2017

by rahul sharma 5

2.1k views

4 votes

2 answers

23

madeeasy
how many foreign keys required for the following relation R (ABCDEF) with FD ( AB ⇒C,BC ⇒A , AC ⇒B ,D ⇒E) into BCNF and lossless join, dependency preserving decomposition?

nimesh kumar asked in Databases Jul 30, 2016

by nimesh kumar

1.9k views

3 votes

2 answers

24

Made easy
Consider the following relation R (A B C D E) WITH FD F= (A ⇒BC, CD ⇒E, B⇒D, E ⇒A ). How many minimum relations required to decompose into BCNF with Dependency preserving and Lossless join decomposition?

nimesh kumar asked in Databases Jul 29, 2016

by nimesh kumar

8.7k views

–1 vote

7 answers

25

BCNF
Every BCNF decomposition is A)Dependency preserving B)not a dependency preserving C)Need not be dependency preserving D)None of the above

vivekpinto07 asked in Databases Jun 19, 2016

by vivekpinto07

2.0k views

1 vote

1 answer

26

Bcnf decomposition proper procedure?
R(ABCDE) {A→BC, CD→E, B→D, E→A} How to convert it into bcnf? I hv seen 2-3 ways to convert into bcnf. And i dont find it possible to convert into bcnf with dependency preserving. Is there ... join for a database in bcnf is tht joining of the decomposed table or relation will give complete relation set. Plz someone explain it

khushtak asked in Databases Jan 18, 2016

615 views

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