What is the purpose of the remove() method for lists and tuples?

Consider two database relations R and S having 3 tuples in R and 2 tuples in S. what is the maximum number of tuples that could appear in the natural join of R and S?

A

2

B

5

C

3

D

6

Which one of the following provides the ability to query information from the database and to insert tuples into, delete tuples from, and modify tuples in the database?

A

DML(Data Manipulation Langauge)

B

DDL(Data Definition Langauge)

C

Query

D

Relational Schema

Which of the following statements are true? i) practical application of XOR linked lists are in environments with limited space requirements, such as embedded devices. ii)xor lists are not suitable because most garbage collectors will fail to work properly with classes or structures that don’t contain literal pointers iii)in order to calculate the address of the next node you need to remember the address of the previous node iv)xor lists are much efficient than single, doubly linked lists and arrays

A

i, ii, iii, iv

B

i, ii, iii

C

i, ii

D

i

What is the purpose of the clear() method for lists and tuples?

A

Removes all elements from the list or tuple

B

Adds an element to the list or tuple

C

Removes the last element

D

Deletes the list or tuple

What is the purpose of the reverse() method for lists and tuples?

A

Reverses the order of elements in the list or tuple

B

Removes the last element

C

Deletes the list or tuple

D

Adds an element to the list or tuple

What is the purpose of the count() method for lists and tuples?

A

Counts the occurrences of a specific element

B

Adds the elements of one list or tuple to another

C

Finds the index of a specific element

D

Reverses the list or tuple

Consider two relations R1(A, B) with the tuples (1, 5), (3, 7) and R2(A, C) = (1, 7), (4, 9). Assume that R(A, B, C) is the full natural outer join of R1 and R2. Consider the following tuples of the form (A, B, C): a = (1, 5, null), b = (1, null, 7), c = (3, null, 9), d = (4, 7, null), e = (1, 5, 7), f = (3, 7, null), g = (4, null, 9). Which one of the following statements is correct?

A

R contains a, b, e, f, g but not c, d.

B

R contains all of a, b, c, d, e, f, g.

C

R contains e, f, g but not a, b.

D

R contains e but not f, g.

SQL allows duplicate tuples in relations, and correspondingly defines the multiplicity of tuples in the result of joins. Which one of the following queries always gives the same answer as the nested select * from R where a in (select S.a from S)

A

select R.* from R, S where R.a = S.a

B

select distinct R.* from R, S where R.a = S.a

C

select R.* from R,(select distinct a from S) as S1 where R.a = S1.a

D

select R.* from R,S where R.a = S.a and is unique R

Which of the following Relational Algebra operations can be used when you want to keep all the tuples of the first relation irrespective of whether or not they have matching tuples in the second relation?

A

Natural join

B

Left-outer join

C

Right-outer-join

D

Theta join

A ________ on an attribute of a relation is a data structure that allows the database system to find those tuples in the relation that have a specified value for that attribute efficiently, without scanning through all the tuples of the relation.

A

Index

B

Reference

C

Assertion

D

Timestamp

What is the purpose of the remove() method for lists and tuples?

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