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Recent questions tagged candidate-key

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DBMS
The correct answer is a and d. I just wanted to know that why not b and c. It is possible that it may be speed and color is also a candidate key. If you have any clarification on this let me know!!!

gateexplore asked in Databases Sep 22, 2023

459 views

2 votes

1 answer

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made easy test series 2023
Consider a relation R having seven attributes ABCDEFG. Fields of R contain only atomic values. FDs = {CD → G, A → BC, B → CF, E → A, F → EG, G → D} is set of functional dependencies. So, how many candidates key does the relation R have?

kaustubh7 asked in Databases Sep 20, 2023

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1 vote

1 answer

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Made easy || Database
Consider a relation schema r(A, B, C, D, E, F) and attribute A is element of every candidate key of r. Maximum number of possible candidate keys of r is ________.

Shreya2002 asked in Databases Aug 9, 2022

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1 answer

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Test Series 2022
Please explain Ans is 22

SKMAKM asked in Databases Aug 6, 2022

by SKMAKM

710 views

1 vote

0 answers

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Finding Candidate Keys | Class Practice | Unacademy
Find the candidate key(s) of the relation R(UVWXYZ) with FD set F={UV-->W, XW-->Y, U-->XZ, Y-->U} XW UV, YV, WXV YUV, XV, WV None of these

anupamsworld asked in Databases Jul 29, 2022

by anupamsworld

532 views

2 votes

1 answer

6

NIELIT Scientific Assistant A 2020 November: 72
Let $\text{R=(A,B,C,D,E)}$ having following $\text{FDs}.\;\text{F}=\{\text{A}\rightarrow \text{BC, CD} \rightarrow \text{E, B}\rightarrow \text{D, E}\rightarrow \text{A}\}.$ Which of the following is not a Candidate key? $\text{A}$ $\text{B}$ $\text{E}$ $\text{BC}$

gatecse asked in Databases Dec 9, 2020

428 views

2 votes

1 answer

7

NIELIT Scientific Assistant A 2020 November: 86
A minimal super key (i.e, one of the super keys for which no proper subset is a superkey) is called: Super Key Candidate Key Primary Key Both Candidate and Primary Key

gatecse asked in Databases Dec 9, 2020

470 views

4 votes

3 answers

8

NIELIT 2016 MAR Scientist B - Section C: 43
Let $R=(A,B,C,D,E,F)$ be a relation scheme with the following dependencies: $C\to F,E\to a,EC\to D, A\to B$. Which of the following is a key for $R$? $CD$ $EC$ $AE$ $AC$

admin asked in Databases Mar 31, 2020

by admin

950 views

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2 answers

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NIELIT 2016 DEC Scientist B (IT) - Section B: 36
The primary key is selected from the: Composite keys Determinants Candidate keys Foreign keys

admin asked in Databases Mar 31, 2020

by admin

937 views

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1 answer

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NIELIT 2016 DEC Scientist B (CS) - Section B: 54
If there is more than one key for relation schema in DBMS then each key in relation schema is classified as prime key super key candidate key primary key

admin asked in Databases Mar 31, 2020

by admin

2.8k views

1 vote

7 answers

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UGC NET CSE | January 2017 | Part 3 | Question: 8
Which one is correct w.r.t. RDBMS? primary key $\subseteq$ super key $\subseteq$ candidate key primary key $\subseteq$ candidate key $\subseteq$ super key super key $\subseteq$ candidate key $\subseteq$ primary key super key $\subseteq$ primary key $\subseteq$ candidate key

go_editor asked in Databases Mar 24, 2020

2.7k views

1 vote

2 answers

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UGC NET CSE | June 2019 | Part 2 | Question: 35
Which of the following key constraints is required for functioning of foreign key in the context relational databases? Unique key Primary key Candidate key Check key

Arjun asked in Databases Jul 2, 2019

by Arjun

3.5k views

2 votes

1 answer

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UGC NET CSE | June 2019 | Part 2 | Question: 36
In relational database management, which of the following is/are property/properties of candidate key? P: Uniqueness Q: Irreducibility P only Q only Both P and Q Neither P nor Q

Arjun asked in Databases Jul 2, 2019

by Arjun

2.5k views

3 votes

2 answers

14

Made easy mock test 1 DBMS super keys
Consider the following relation R(A1, A2,...A15) with (A1,A2, ... A6) of relation R are simple candidate key. The number of possible superkey in relation R is_

Ram Swaroop asked in Databases Jan 30, 2019

1.3k views

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0 answers

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Self-doubt [Foreign keys and Third Normal Form]
I've some elementary doubts regarding Foreign keys (referential integrity) : Can a foreign key consist of a collection of attributes - ie. can two or more columns collectively form a foreign key? If foreign key ... Multiple candidate keys Composite candidate keys Overlapping candidate keys If possible, please provide an example. Thank You.!

Harsh Kumar asked in Databases Nov 19, 2018

960 views

1 vote

0 answers

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Self doubt
Can Prime attribute be NULL in any of the the Candidate key ?? Can Prime attribute be NULL in Primary key ??

jatin khachane 1 asked in Databases Oct 23, 2018

by jatin khachane 1

378 views

0 votes

1 answer

17

Super Keys
How many Super keys Possible for R(A,B,C,D,E) with 1. {A,BC,DE} as the keys ? 2. {A,BC,CDE} as the keys ?

Na462 asked in Databases Oct 13, 2018

by Na462

815 views

1 vote

2 answers

18

General doubt dbms
An instance of a relational schema R(A,B,C,D) has distinct values for attribute A then A can be 1) candidate key 2)non key 3)super key 4)none

Shivani gaikawad asked in Databases Sep 14, 2018

by Shivani gaikawad

487 views

0 votes

0 answers

19

Gate 2004 doubt on foreign keys
Referencing to this gate ques- https://gateoverflow.in/16095/gate2004_13-let-and-two-relation-schema-where-the-primary-key Let R1 (A, B, C) and R2 (D, E) be two relation schema, where the primary keys are shown underlined, and let C be a ... subtracting entities of D from C can still have null and other values(those were duplicate). So, how will it get empty set?

bts1jimin asked in Databases Sep 1, 2018

986 views

2 votes

1 answer

20

MadeEasy Test Series: Databases - Candidate Keys
Relation R(A1, A2, A3 ..... An) n attributes. On this relation m simple candidate key (m ≤ n). How many super keys possible in this relation? A. 2m – 1 B. (2n – 1) ⋅ 2n-m C. 2n – 1 D. (2m – 1) 2n-m One way is by taking instances and solve it, but plz without it what's the logic behind the answer?

Na462 asked in Databases May 17, 2018

by Na462

3.4k views

1 vote

1 answer

21

No of Super Key
R (A1, A2, ….An) and every (n-2) attributes of R forms a candidate key. How many super keys are there in R? a) $_{n-2}^{n}\textrm{C}$ b) $_{n-2}^{n}\textrm{C}$ * 4 c) $_{n-2}^{n}\textrm{C}$ * n d) $_{n-2}^{n}\textrm{C}$ + n +1

hacker16 asked in Databases Jan 17, 2018

2.7k views

1 vote

2 answers

22

garam_masala_ asked in Databases Nov 21, 2017

by garam_masala_

453 views

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Recent questions tagged candidate-key