Recent questions tagged database-normalization

0 votes

1 answer

1

Self doubt
Join of two 3NF relations may be yeilds a 3NF relation True/False? If true explain with example? If false explain why?

asked Aug 7 in Databases by eswaraleti143 (17 points) | 25 views

+1 vote

2 answers

2

Keys in a Decomposition
Relation $R=(L, M, N, O, P)$ $R$ is decomposed into $R_{1} = (L, M, N, P)$ and $R_{2} = (M, O).$ for $R_{1}$ dependencies are $P->L, L->MN$ $1)$What are keys for $R_{1}$? $2)$What normal form it holds?

asked Jul 15 in Databases by srestha Veteran (91.8k points) | 60 views

0 votes

0 answers

3

BCNF Decomposition

asked Jul 14 in Databases by Na462 Active (4.5k points) | 42 views

0 votes

1 answer

4

Database Normal forms
Given a relation R(ABCD) with functional dependencies: $AB \to CD\\ BC \to D$ Normal form is? 1) 1 NF 2) 2 NF 3) 3 NF 4) BCNF

asked Jul 10 in Databases by cynicthnkr (109 points) | 38 views

0 votes

2 answers

5

Normalization - 3NF doubt
A relation has the attributes R(ABCDEPG). The set of Functional Dependencies are : $F: { AB \to CD, DE \to P, C\to E, P\to C, B \to G }$ After normalising this relation till 3NF, I get the following tables : ${ ... A LOSSLESS AND DEPENDENCY PRESERVING PROPERTY IN 3NF - But I am not getting the Dependency Preservation property. Is something wrong with the decomposition ?

asked Jul 4 in Databases by Harsh Kumar Junior (587 points) | 59 views

0 votes

1 answer

6

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 ?

asked Jun 23 in Databases by karthikmenon (11 points) | 93 views

0 votes

1 answer

7

normalization
proof that a relation with the two attribute is always in BCNF....

asked Jun 23 in Databases by vijju532 (369 points) | 47 views

0 votes

0 answers

8

Closure of a set of functional dependency

asked Jun 22 in Databases by Harsh Kumar Junior (587 points) | 55 views

0 votes

2 answers

9

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?

asked Jun 8 in Databases by pradeepchaudhary (179 points) | 93 views

+1 vote

0 answers

10

Hacker Earth Normalization Question
A particular database is normalized to satisfy a particular level of normalization (either 1NF or 2NF or 3NF). One of the tables contains, among other fields, a column for the City and a column for the Zip Code. Assuming that there is a many-to-one mapping ... , we may conclude that the database is definitely NOT in xNF form. What is the integer x (1, 2, or 3)?

asked Jun 8 in Databases by pradeepchaudhary (179 points) | 76 views

+1 vote

1 answer

11

Normal Forms
Which of the following statement false of relation $R$ is in $3NF$ but not $BCNF$? Relation $R$ must consist atleast two over-lapped candidate keys. Relation $R$ must consist proper subset of candidate key determines proper subset of some other ... other candidate keys simple candidate key. Relation $R$ must consist atleast two compound candidate keys. Please Explain every Option.

asked May 29 in Databases by Na462 Active (4.5k points) | 81 views

0 votes

1 answer

12

2NF Question.
Given a table $R(ABCDEF)$ $ABC -> D$ $ABD -> E$ $CD -> F$ $CDF -> B$ $BF -> D$ It's candidate keys are $ABC, ACD.$ So while checking for $2NF$, Can I say that $ABD -> E$ is not partially dependent because $ABD$ as a whole is not a part of candidate key even though $AB$ is a part of candidate key.

asked May 27 in Databases by Rahul Ranjan 1 (141 points) | 44 views

+1 vote

0 answers

13

Relations
Consider the following relational schema $R(ABCDEFG)$ with $FD$ set $\{AB → C, BC → A, AC → B, B → D, D → E\}$. The minimum relations required to decompose $R$ into $BCNF$ which satisfy lossless join and dependency preserving decomposition is ________.

asked May 26 in Databases by Na462 Active (4.5k points) | 67 views

0 votes

1 answer

14

Candidate Keys
Consider the following relation $R(A, B, C, D, E, F, G, H)$. The maximum number of super keys possible if $4$ simple candidate keys in relation $R$ are ________. Solution. What i did is $^8C_4 + ^8C_5 + ^8C_6 + ^8C_7 + ^8C_8 = 163$ Is it wrong ? and why

asked May 26 in Databases by Na462 Active (4.5k points) | 46 views

0 votes

1 answer

15

Self - Doubt : How to calculate candidate keys in decomposed Relation?

asked May 1 in Databases by Durgesh Singh Junior (877 points) | 74 views

0 votes

1 answer

16

Normalization-(prime attribute -> prime attribute dependency is there in BCNF)

asked Apr 11 in Databases by srestha Veteran (91.8k points) | 87 views

+1 vote

3 answers

17

Lossy or Lossless
Consider the relation $R(ABCDEG)$ and $FD's$ are $\{AB \rightarrow C,AC \rightarrow B,AD \rightarrow E,B \rightarrow D,BC \rightarrow A,E \rightarrow G\}$ then the decomposition$\{ABC,ACDE,ADG\}$ is lossless and not dependency preserving is not lossless and dependency preserving is lossless and dependency preserving is not lossless and not dependency preserving

asked Mar 19 in Databases by shivanisrivarshini Boss (14.1k points) | 143 views

+6 votes

3 answers

18

GATE2018-42
Consider the following four relational schemas. For each schema , all non-trivial functional dependencies alre listed, The bolded attributes are the respective primary keys. Schema I: Registration(rollno, courses) Field courses' is a set-valued attribute containing the set ... Which one of the relational schemas above is in 3NF but not in BCNF? Schema I Schema II Schema III Schema IV

asked Feb 14 in Databases by gatecse Boss (18.1k points) | 1.5k views

+1 vote

0 answers

19

normalization
what is procedure to convert one normal form to another normal form ??? i.e. how to convert 1NF to 2NF ? please explain with example

asked Jan 30 in Databases by Rahul_Rathod_ (359 points) | 42 views

+2 votes

1 answer

20

MADE EASY test series - Minimum relations required in 2NF form?

asked Jan 28 in Databases by tarunmaganti (265 points) | 136 views

+1 vote

1 answer

21

3NF Normalization Doubt
Is a relation with multiple candidate keys in 3NF? According to this, As per the first definition any relation having multiple candidate keys will have transitive dependency to a non key attribute. My Inference : Since it has a Transitive dependency ... given is correct or not.And if it is correct can you please provide some other reference illustrating the same concept.

asked Jan 25 in Databases by Sourajit25 Junior (825 points) | 73 views

+1 vote

1 answer

22

Normal Form
Given a relation with five attributes and the following FDs: A -> D A -> E DE -> BC B -> A D -> C What is the highest normal form satisfied by the relation?

asked Jan 13 in Databases by Tuhin Dutta Loyal (7.9k points) | 152 views

0 votes

2 answers

23

Ace Test - Database

asked Jan 12 in Databases by hacker16 Active (2.7k points) | 85 views

+2 votes

1 answer

24

Test Series

asked Jan 10 in Databases by vishal chugh Active (1.7k points) | 140 views

+3 votes

2 answers

25

BCNF, lossless, functional dependency preserving.

asked Jan 7 in Databases by Hemant Parihar Boss (14.9k points) | 254 views

+1 vote

2 answers

26

Highest normal form achieved by given $FDs$ is?

asked Dec 31, 2017 in Databases by Aghori Loyal (6.1k points) | 104 views

0 votes

1 answer

27

normalization

asked Dec 21, 2017 in Databases by Meenakshi Sharma Active (3k points) | 62 views

+1 vote

1 answer

28

Normal Forms

asked Dec 17, 2017 in Databases by ankitgupta.1729 Loyal (6.6k points) | 99 views

0 votes

0 answers

29

[DBMS] Decompose into BCNF and 4NF
Minimum relations to decompose into BCNF and 4NF.List only relation names with attributes and total number of relations

asked Dec 15, 2017 in Databases by rahul sharma 5 Boss (24.5k points) | 134 views

0 votes

0 answers

30

NORMALIZATION
WHICH OF THE FOLLOWING IS CORRECT IF RELATION R IS IN 3NF 1. NO NON PRIME ATTRIBUTE OF R IS TRANSITIVELY DEPENDENT ON KEY(SUPER KEY,PRIMARY KEY,CANDIDATE KEY). 2.PRIME ATTRIBUTE OF R CAN BE TRANSITIVELY DEPENDENT ON KEY(SUPER KEY,PRIMARY KEY,CANDIDATE KEY). 3. A ... R. 4.A relation R is in 3NF, if every non-prime attribute of R, is fully functionally dependent on every key of R.

asked Dec 13, 2017 in Databases by Jaspreet Kaur Bains Junior (759 points) | 124 views

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