Consider the following relations A, B and C:

**A. ** 4

**B. ** 3

**C. ** 0

**D. ** 1

**Answer : ****Option B**

**Explaination / Solution: **

As the result of subquery is an empty table, ‘>ALL’ comparison is true . Therefore, all the three row id’s of A will be selected from table A.

How many tuples does the result of the following SQL query contain?

SELECT A.Id

FROM A

WHERE A.Age > ALL(SELECT B.Age FROM B
WHERE B.Name = ‘Arun’)

As the result of subquery is an empty table, ‘>ALL’ comparison is true . Therefore, all the three row id’s of A will be selected from table A.

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Consider the following relations A, B and C:

**A. ** 7

**B. ** 4

**C. ** 5

**D. ** 9

**Answer : ****Option A**

**Explaination / Solution: **

How many tuples does the result of the following relational algebra expression contain?
Assume that the schema of A ∪ B is the same as that of A.

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A relational schema for a train reservation database is given below

**A. ** 1,0

**B. ** 1,2

**C. ** 1,3

**D. ** 1,5

**Answer : ****Option D**

**Explaination / Solution: **

No Explaination.

Passenger (pid, pname, age)

Reservation (pid, cass, tid)

What pids are returned by the following SQL query for the above instance of the
tables?

SELECT pid

FROM Reservation

WHERE class ' AC ' AND

EXISTS (SELECT *
FROM Passenger
WHERE age> 65 AND
Passenger.pid = Reservation.pid)

No Explaination.

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Which of the following assertions are CORRECT? **A. ** P, Q

**B. ** Q, R

**C. ** P, R

**D. ** R, S

**Answer : ****Option C**

**Explaination / Solution: **

P and R always hold true Else consider a sample set {1, 2, 3, 4} and check accordingly

P: Adding 7 to each entry in a list adds 7 to the mean of the list

Q: Adding 7 to each entry in a list adds 7 to the standard deviation of the list

R: Doubling each entry in a list doubles the mean of the list

S: Doubling each entry in a list leaves the standard deviation of the list unchanged

P and R always hold true Else consider a sample set {1, 2, 3, 4} and check accordingly

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Suppose the predicate F(x, y, t) is used to represent the statement that person x
can fool person y at time t. which one of the statements below expresses best
the meaning of the formula ∀x ∃y ∃t (¬F (x, y, t))?

**A. ** Everyone can fool some person at some time

**B. ** No one can fool everyone all the time

**C. ** Everyone cannot fool some person all the time

**D. ** No one can fool some person at some time

**Answer : ****Option D**

**Explaination / Solution: **

No Explaination.

No Explaination.

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An index is clustered, if

**A. ** it is on a set of fields that form a candidate key

**B. ** it is on a set of fields that include the primary key

**C. ** the data records of the file are organized in the same order as the data entries of the index

**D. ** the data records of the file are organized not in the same order as the data entries of the index

**Answer : ****Option C**

**Explaination / Solution: **

Clustered index is built on ordering non key field and hence if the index is clustered then the data records of the file are organized in the same order as the data entries of the index.

Clustered index is built on ordering non key field and hence if the index is clustered then the data records of the file are organized in the same order as the data entries of the index.

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The following functional dependencies hold for relations R(A, B, C) and S(B, D, E) B → A,
A → C The relation R contains 200tuples and the relation S contains 100tuples. What is
the maximum number of tuples possible in the natural join R S?

**A. ** 100

**B. ** 200

**C. ** 300

**D. ** 2000

**Answer : ****Option A**

**Explaination / Solution: **

No Explaination.

No Explaination.

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Using public key cryptography, X adds a digital signature σ to message M, encrypts , and sends it to Y, where it is decrypted. Which one of the following sequences of keys is
used for the operations?

**A. ** Encryption: X’s private key followed by Y’s private key; Decryption: X’s public key followed by Y’s public key

**B. ** Encryption: X’s private key followed by Y’s public key; Decryption: X’s public key followed by Y’s private key

**C. ** Encryption: X’s public key followed by Y’s private key; Decryption: Y’s public key followed by X’s private key

**D. ** Encryption: X’s private key followed by Y’s public key; Decryption: Y’s private key followed by X’s public key

**Answer : ****Option D**

**Explaination / Solution: **

Encryption: Source has to encrypt with its p r ivate key for formin g Digital signature for Authentication. source has to encrypt the <M, σ > with Y ' s
public key to send it confidentially

Decryption: Destination Y has to decrypt first with its private key, then decrypt using source public key

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A hash table of length 10 uses open addressing with hash function h(k)=k
mod 10, and linear probing. After inserting 6 values into an empty hash table,
the table is as shown below **A. ** 46, 42, 34, 52, 23, 33

**B. ** 34, 42, 23, 52, 33, 46

**C. ** 46, 34, 42, 23, 52, 33

**D. ** 42, 46, 33, 23, 34, 52

**Answer : ****Option C**

**Explaination / Solution: **

No Explaination.

Which one of the following choices gives a possible order in which the key values
could have been inserted in the table?

No Explaination.

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A hash table of length 10 uses open addressing with hash function h(k)=k
mod 10, and linear probing. After inserting 6 values into an empty hash table,
the table is as shown below

**A. ** 10

**B. ** 20

**C. ** 30

**D. ** 40

**Answer : ****Option B**

**Explaination / Solution: **

No Explaination.

How many different insertion sequences of the key values using the same hash
function and linear probing will result in the hash table shown above?

No Explaination.

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