Databases - Superkeys

Consider the relation R(A,B,C,D,E) with the functional dependencies :A → B, B → C, C → A, D → E, and E → DThe Maximum possible super-keys of R is ______________...

naveen bhatt

1.4k views

naveen bhatt asked Dec 7, 2018

Databases
made-easy-test-series
databases
database-normalization
superkeys

+ –

2 votes

1 answer

Na462 asked May 17, 2018

3,439 views

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?

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 – 1B. (2n – 1) �...

Na462

3.4k views

Na462 asked May 17, 2018

Databases
databases
superkeys
candidate-key
made-easy-test-series

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5 votes

2 answers

Tushar Shinde asked Jan 18, 2016

1,185 views

MadeEasy Test Series: Databases - Super Keys
Consider a relation $R$ with $2n$ attributes. Assume any $2n/2$ of the attributes constitutes key. Total number of super keys possible are: $^{2n}C_{2^{n-1}}\times \left(2\right)^{2^{n-1}}$ $^{2n}C_{2^{n-1}} + \left(2\right)^{2^{n-1}}$ $^{2n}C_{2^{n-1}} - \left(2\right)^{2^{n-1}}$ $^{2n}C_{2^{n-1}} \div \left(2\right)^{2^{n-1}}$

Consider a relation $R$ with $2n$ attributes. Assume any $2n/2$ of the attributes constitutes key. Total number of super keys possible are:$^{2n}C_{2^{n-1}}\times \left(2...

Tushar Shinde

1.2k views

Tushar Shinde asked Jan 18, 2016

Databases
made-easy-test-series
databases
superkeys

+ –

4 votes

1 answer

Akash Kanase asked Jan 15, 2016

734 views

TestBook Test Series: Databases - Super Keys
I think here even with Ph is removed from table we still get 12 Super keys. Because Salary & One of CK must be there.

I think here even with Ph is removed from table we still get 12 Super keys. Because Salary & One of CK must be there.

Akash Kanase

734 views

Akash Kanase asked Jan 15, 2016

Databases
testbook-test-series
databases
database-normalization
superkeys

+ –

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