McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Computer Science Engineering (CSE) , Bachelor of Science in Computer Science FY (BSc CS) , Bachelor of Science in Computer Science SY (BSc CS) , Bachelor of Science in Information Technology SY (BSc IT) , Bachelor of Computer Applications (BCA) .
Chapters
| 101. |
The term _______ is used to refer to a row. |
| A. | Attribute |
| B. | Tuple |
| C. | Field |
| D. | Instance |
| Answer» B. Tuple | |
| 102. |
The term attribute refers to a ___________ of a table. |
| A. | Record |
| B. | Column |
| C. | Tuple |
| D. | Key |
| Answer» B. Column | |
| 103. |
For each attribute of a relation, there is a set of permitted values, called the ________ of that attribute. |
| A. | Domain |
| B. | Relation |
| C. | Set |
| D. | Schema |
| Answer» A. Domain | |
| 104. |
Database __________ which is the logical design of the database, and the database _______ which is a snapshot of the data in the database at a given instant in time. |
| A. | Instance, Schema |
| B. | Relation, Schema |
| C. | Relation, Domain |
| D. | Schema, Instance |
| Answer» D. Schema, Instance | |
| 105. |
Course(course_id,sec_id,semester) Here the course_id,sec_id and semester are __________ and course is a _________ |
| A. | Relations, Attribute |
| B. | Attributes, Relation |
| C. | Tuple, Relation |
| D. | Tuple, Attributes |
| Answer» B. Attributes, Relation | |
| 106. |
Department (dept name, building, budget) and Employee (employee_id, name, dept name, salary) Here the dept_name attribute appears in both the relations. Here using common attributes in relation schema is one way of relating ___________ relations. |
| A. | Attributes of common |
| B. | Tuple of common |
| C. | Tuple of distinct |
| D. | Attributes of distinct |
| Answer» C. Tuple of distinct | |
| 107. |
A domain is atomic if elements of the domain are considered to be ____________ units. |
| A. | Different |
| B. | Indivisbile |
| C. | Constant |
| D. | Divisible |
| Answer» B. Indivisbile | |
| 108. |
The tuples of the relations can be of ________ order. |
| A. | Any |
| B. | Same |
| C. | Sorted |
| D. | Constant |
| Answer» A. Any | |
| 109. |
Choose the correct statement regarding superkeys |
| A. | A superkey is an attribute or a group of multiple attributes that can uniquely identify a tuple |
| B. | A superkey is a tuple or a set of multiple tuples that can uniquely identify an attribute |
| C. | Every superkey is a candidate key |
| D. | A superkey is an attribute or a set of attributes that distinguish the relation from other relations |
| Answer» A. A superkey is an attribute or a group of multiple attributes that can uniquely identify a tuple | |
| 110. |
What is an Instance of a Database? |
| A. | The logical design of the database system |
| B. | The entire set of attributes of the Database put together in a single relation |
| C. | The state of the database system at any given point of time |
| D. | The initial values inserted into the Database immediately after its creation |
| Answer» C. The state of the database system at any given point of time | |
| 111. |
What is a foreign key? |
| A. | A foreign key is a primary key of a relation which is an attribute in another relation |
| B. | A foreign key is a superkey of a relation which is an attribute in more than one other relations |
| C. | A foreign key is an attribute of a relation that is a primary key of another relation |
| D. | A foreign key is the primary key of a relation that does not occur anywhere else in the schema |
| Answer» C. A foreign key is an attribute of a relation that is a primary key of another relation | |
| 112. |
What action does ⋈ operator perform in relational algebra |
| A. | Output specified attributes from all rows of the input relation and remove duplicate tuples from the output |
| B. | Outputs pairs of rows from the two input relations that have the same value on all attributes that have the same name |
| C. | Output all pairs of rows from the two input relations (regardless of whether or not they have the same values on common attributes) |
| D. | Return rows of the input relation that satisfy the predicate |
| Answer» A. Output specified attributes from all rows of the input relation and remove duplicate tuples from the output | |
| 113. |
What does the “x” operator do in relational algebra? |
| A. | Output specified attributes from all rows of the input relation. Remove duplicate tuples from the output |
| B. | Output pairs of rows from the two input relations that have the same value on all attributes that have the same name |
| C. | Output all pairs of rows from the two input relations (regardless of whether or not they have the same values on common attributes) |
| D. | Returns the rows of the input relation that satisfy the predicate |
| Answer» C. Output all pairs of rows from the two input relations (regardless of whether or not they have the same values on common attributes) | |
| 114. |
An attribute is a __________ in a relation. |
| A. | Row |
| B. | Column |
| C. | Value |
| D. | Tuple |
| Answer» B. Column | |
| 115. |
What is the method of specifying a primary key in a schema description? |
| A. | By writing it in bold letters |
| B. | By underlining it using a dashed line |
| C. | By writing it in capital letters |
| D. | By underlining it using a bold line |
| Answer» D. By underlining it using a bold line | |
| 116. |
Statement 1: A tuple is a row in a relation Statement 2: Existence of multiple foreign keys in a same relation is possible |
| A. | Both the statements are true |
| B. | Statement 1 is correct but Statement 2 is false |
| C. | Statement 1 is false but Statement 2 is correct |
| D. | Both the statements are false |
| Answer» A. Both the statements are true | |
| 117. |
Choose the option that correctly explains in words, the function of the following relational algebra expression σyear≥2009 (book ⋈ borrow) |
| A. | Selects all tuples from the Cartesian product of book and borrow |
| B. | Selects all the tuples from the natural join of book and borrow wherever the year is lesser than 2009 |
| C. | Selects all the tuples from the natural join of book and student wherever the year is greater than or equal to 2009 |
| D. | Selects all tuples from the Cartesian product of book and borrow wherever the year is greater than or equal to 2009 |
| Answer» B. Selects all the tuples from the natural join of book and borrow wherever the year is lesser than 2009 | |
| 118. |
State true or false: If a relation consists of a foreign key, then it is called a referenced relation of the foreign key dependency. |
| A. | True |
| B. | False |
| C. | none |
| D. | all |
| Answer» B. False | |
| 119. |
Which of the following information does an SQL DDL not specify? |
| A. | The schema for each relation |
| B. | The integrity constraints |
| C. | The operations on the tuples |
| D. | The security and authorization information for each relation |
| Answer» C. The operations on the tuples | |
| 120. |
Which of the following data types does the SQL standard not support? |
| A. | char(n) |
| B. | String(n) |
| C. | varchar(n) |
| D. | float(n) |
| Answer» B. String(n) | |
| 121. |
Which command is used to create a new relation in SQL |
| A. | create table( , …) |
| B. | create relation( , …) |
| C. | new table( , …) |
| D. | new relation( , …) |
| Answer» A. create table( , …) | |
| 122. |
If a1, a2, a3 are attributes in a relation and S is another relation, which of the following is an incorrect specification of an integrity constraint? |
| A. | primary key(a1, a2, a3) |
| B. | primary key(a1) |
| C. | foreign key(a1, a2) references S |
| D. | foreign key(a1, a2) |
| Answer» D. foreign key(a1, a2) | |
| 123. |
What is the syntax to load data into the database? (Consider D as the database and a, b, c as datA:) |
| A. | enter into D (a, b, C:); |
| B. | insert into D values (a, b, C:); |
| C. | insert into D (a, b, C:); |
| D. | insert (a, b, C:) values into D; |
| Answer» B. insert into D values (a, b, C:); | |
| 124. |
Which of the following commands do we use to delete a relation (R) from a database? |
| A. | drop table R |
| B. | drop relation R |
| C. | delete table R |
| D. | delete from R |
| Answer» A. drop table R | |
| 125. |
Which of the following commands do we use to delete all the tuples from a relation (R)? |
| A. | delete table R |
| B. | drop table R |
| C. | delete from R |
| D. | drop from R |
| Answer» C. delete from R | |
| 126. |
Choose the correct command to delete an attribute A from a relation R |
| A. | alter table R delete A |
| B. | alter table R drop A |
| C. | alter table drop A from R |
| D. | delete A from R |
| Answer» B. alter table R drop A | |
| 127. |
create table apartment(ownerID varchar (5), ownername varchar(25), floor numeric(4,0),
|
| A. | The statement is syntactically wrong |
| B. | It creates a relation with three attributes ownerID, ownername, floor in which floor cannot be null. |
| C. | It creates a relation with three attributes ownerID, ownername, floor in which ownerID cannot be null. |
| D. | It creates a relation with three attributes ownerID, ownername, floor in which ownername must consist of at least 25 characters. |
| Answer» C. It creates a relation with three attributes ownerID, ownername, floor in which ownerID cannot be null. | |
| 128. |
What does the notnull integrity constraint do? |
| A. | It ensures that at least one tuple is present in the relation |
| B. | It ensures that at least one foreign key is present in the relation |
| C. | It ensures that all tuples have a finite value on a specified attribute |
| D. | It ensures that all tuples have finite attributes on all the relations |
| Answer» C. It ensures that all tuples have a finite value on a specified attribute | |
| 129. |
Which SQL function is used to count the number of rows in a SQL query? |
| A. | COUNT() |
| B. | NUMBER() |
| C. | SUM() |
| D. | COUNT(*) |
| Answer» D. COUNT(*) | |
| 130. |
Which SQL keyword is used to retrieve a maximum value? |
| A. | MOST |
| B. | TOP |
| C. | MAX |
| D. | UPPER |
| Answer» C. MAX | |
| 131. |
Which of the following SQL clauses is used to DELETE tuples from a database table? |
| A. | DELETE |
| B. | REMOVE |
| C. | DROP |
| D. | CLEAR |
| Answer» A. DELETE | |
| 132. |
___________removes all rows from a table without logging the individual row deletions. |
| A. | DELETE |
| B. | REMOVE |
| C. | DROP |
| D. | TRUNCATE |
| Answer» D. TRUNCATE | |
| 133. |
Which of the following is not a DDL command? |
| A. | UPDATE |
| B. | TRUNCATE |
| C. | ALTER |
| D. | None of the Mentioned |
| Answer» A. UPDATE | |
| 134. |
Which of the following are TCL commands? |
| A. | UPDATE and TRUNCATE |
| B. | SELECT and INSERT |
| C. | GRANT and REVOKE |
| D. | ROLLBACK and SAVEPOINT |
| Answer» D. ROLLBACK and SAVEPOINT | |
| 135. |
________________ is not a category of SQL command. |
| A. | TCL |
| B. | SCL |
| C. | DCL |
| D. | DDL |
| Answer» B. SCL | |
| 136. |
If you don’t specify ASC or DESC after a SQL ORDER BY clause, the following is used by default ______________ |
| A. | ASC |
| B. | DESC |
| C. | There is no default value |
| D. | None of the mentioned |
| Answer» A. ASC | |
| 137. |
Which of the following statement is true? |
| A. | DELETE does not free the space containing the table and TRUNCATE free the space containing the table |
| B. | Both DELETE and TRUNCATE free the space containing the table |
| C. | Both DELETE and TRUNCATE does not free the space containing the table |
| D. | DELETE free the space containing the table and TRUNCATE does not free the space containing the table |
| Answer» A. DELETE does not free the space containing the table and TRUNCATE free the space containing the table | |
| 138. |
What is the purpose of the SQL AS clause? |
| A. | The AS SQL clause is used to change the name of a column in the result set or to assign a name to a derived column |
| B. | The AS clause is used with the JOIN clause only |
| C. | The AS clause defines a search condition |
| D. | All of the mentioned |
| Answer» A. The AS SQL clause is used to change the name of a column in the result set or to assign a name to a derived column | |
| 139. |
What does DML stand for? |
| A. | Different Mode Level |
| B. | Data Model Language |
| C. | Data Mode Lane |
| D. | Data Manipulation language |
| Answer» D. Data Manipulation language | |
| 140. |
With SQL, how do you select all the records from a table named “Persons” where the value of the column “FirstName” ends with an “a”? |
| A. | SELECT * FROM Persons WHERE FirstName=’a’ |
| B. | SELECT * FROM Persons WHERE FirstName LIKE ‘a%’ |
| C. | SELECT * FROM Persons WHERE FirstName LIKE ‘%a’ |
| D. | SELECT * FROM Persons WHERE FirstName=’%a%’ |
| Answer» C. SELECT * FROM Persons WHERE FirstName LIKE ‘%a’ | |
| 141. |
With SQL, how can you return all the records from a table named “Persons” sorted descending by “FirstName”? |
| A. | SELECT * FROM Persons SORT BY ‘FirstName’ DESC |
| B. | SELECT * FROM Persons ORDER FirstName DESC |
| C. | SELECT * FROM Persons SORT ‘FirstName’ DESC |
| D. | SELECT * FROM Persons ORDER BY FirstName DESC |
| Answer» D. SELECT * FROM Persons ORDER BY FirstName DESC | |
| 142. |
With SQL, how can you return the number of not null records in the “Persons” table? |
| A. | SELECT COUNT() FROM Persons |
| B. | SELECT COLUMNS() FROM Persons |
| C. | SELECT COLUMNS(*) FROM Persons |
| D. | SELECT COUNT(*) FROM Persons |
| Answer» D. SELECT COUNT(*) FROM Persons | |
| 143. |
What does the ALTER TABLE clause do? |
| A. | The SQL ALTER TABLE clause modifies a table definition by altering, adding, or deleting table columns and/or constraints |
| B. | The SQL ALTER TABLE clause is used to insert data into database table |
| C. | THE SQL ALTER TABLE deletes data from database table |
| D. | The SQL ALTER TABLE clause is used to delete a database table |
| Answer» A. The SQL ALTER TABLE clause modifies a table definition by altering, adding, or deleting table columns and/or constraints | |
| 144. |
The UPDATE SQL clause can _____________ |
| A. | update only one row at a time |
| B. | update more than one row at a time |
| C. | delete more than one row at a time |
| D. | delete only one row at a time |
| Answer» B. update more than one row at a time | |
| 145. |
The UNION SQL clause can be used with _____________ |
| A. | SELECT clause only |
| B. | DELETE and UPDATE clauses |
| C. | UPDATE clause only |
| D. | All of the mentioned |
| Answer» A. SELECT clause only | |
| 146. |
Which SQL statement is used to return only different values? |
| A. | SELECT DIFFERENT |
| B. | SELECT UNIQUE |
| C. | SELECT DISTINCT |
| D. | SELECT ALL |
| Answer» C. SELECT DISTINCT | |
| 147. |
Which SQL keyword is used to sort the result-set? |
| A. | ORDER BY |
| B. | SORT |
| C. | ORDER |
| D. | SORT BY |
| Answer» A. ORDER BY | |
| 148. |
How can you change “Hansen” into “Nilsen” in the “LastName” column in the Persons table? |
| A. | UPDATE Persons SET LastName=’Hansen’ INTO LastName=’Nilsen’ |
| B. | MODIFY Persons SET LastName=’Nilsen’ WHERE LastName=’Hansen’ |
| C. | MODIFY Persons SET LastName=’Hansen’ INTO LastName=’Nilsen’ |
| D. | UPDATE Persons SET LastName=’Nilsen’ WHERE LastName=’Hansen’ |
| Answer» D. UPDATE Persons SET LastName=’Nilsen’ WHERE LastName=’Hansen’ | |
| 149. |
Which of the following command makes the updates performed by the transaction permanent in the database? |
| A. | ROLLBACK |
| B. | COMMIT |
| C. | TRUNCATE |
| D. | DELETE |
| Answer» B. COMMIT | |
| 150. |
Which TCL command undo all the updates performed by the SQL in the transaction? |
| A. | ROLLBACK |
| B. | COMMIT |
| C. | TRUNCATE |
| D. | DELETE |
| Answer» A. ROLLBACK | |
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