Monday, September 28, 2020

Database Systems MCQ

Q.1 The physical location of a record is determined by a mathematical formula that transforms a file key into a record location is :

(A) B-Tree File

(B) Hashed File

(C) Indexed File

(D) Sequential file

Ans: B

 

Q.2 Using Relational Algebra the query that finds customers, who have a balance of over 1000 is

(A) πCustomer_name(s balance >1000(Deposit))

(B) σCustomer_name(Pbalance >1000(Deposit))

(C) πCustomer_name(s balance >1000(Borrow))

(D) σCustomer_name(Pbalance >1000(Borrow))

Ans: A

 

Q.3 A primary key is combined with a foreign key creates

(A) Parent-Child relation ship between the tables that connect them.

(B) Many to many relationship between the tables that connect them.

(C) Network model between the tables that connect them.

(D) None of the above.

Ans: A

 

Q.4 In E-R Diagram derived attribute are represented by

(A) Ellipse

(B) Dashed ellipse

(C) Rectangle

(D) Triangle

Ans B

 

Q.5 Cross Product is a:

(A) Unary Operator

(B) Ternary Operator

(C) Binary Operator

(D) Not an operator

Ans: C

 

Q.6 An instance of relational schema R (A, B, C) has distinct values of A including NULL values. Which one of the following is true?

(A) A is a candidate key

(B) A is not a candidate key

(C) A is a primary Key

(D) Both (A) and (C)

Ans: B

 

Q.7 Consider the join of a relation R with relation S. If R has m tuples and S has n tuples, then the maximum size of join is:

(A) mn

(B) m+n

(C) (m+n)/2

(D) 2(m+n)

Ans: A

 

Q.8 The natural join is equal to :

(A) Cartesian Product

(B) Combination of Union and Cartesian product

(C) Combination of selection and Cartesian product

(D) Combination of projection and Cartesian product

Ans: D

 

Q.9 Which one of the following is not true for a view:

(A) View is derived from other tables.

(B) View is a virtual table.

(C) A view definition is permanently stored as part of the database.

(D) View never contains derived columns.

Ans: C

 

Q.10 A primary key if combined with a foreign key creates

(A) Parent-Child relationship between the tables that connect them.

(B) Many to many relationship between the tables that connect them.

(C) Network model between the tables that connect them.

(D) None of the above.

Ans: A

 

Q.11 In E-R Diagram relationship type is represented by

(A) Ellipse

(B) Dashed ellipse

(C) Rectangle

(D) Diamond

Ans: D

 

Q.12 Hierarchical model is also called

(A) Tree structure

(B) Plex Structure

(C) Normalize Structure

(D) Table Structure

Ans: A

 

Q.13 To delete a particular column in a relation the command used is:

(A) UPDATE

(B) DROP

(C) ALTER

(D) DELETE

Ans: C

 

Q.14 The ______ operator is used to compare a value to a list of literals values that have been specified.

(A) BETWEEN

(B) ANY

(C) IN

(D) ALL

Ans: A

 

Q.15 A logical schema

A) is the entire database

B) is a standard way of organizing information into a accessible part

C) describe how data is actually stored on disk

D) none of these

Ans: D

 

Q.16 A B-tree of order m has maximum of _____________ children

(A) m

(B) m+1

(C) m-1

(D) m/2

Ans: A

 

Q.17 _____________ function divides one numeric expression by another and returns the remainder.

(A) POWER

(B) MOD

(C) ROUND

(D) REMAINDER

Ans: B

 

Q.18 A data manipulation command the combines the records from one or more tables is called

(A) SELECT

(B) PROJECT

(C) JOIN

(D) PRODUCT

Ans: C

 

Q.19 In E-R diagram generalization is represented by

(A) Ellipse

(B) Dashed ellipse

(C) Rectangle

(D) Triangle

Ans: D

 

Q.20 _________ is a virtual table that draws its data from the result of an SQL SELECT statement.

(A) View

(B) Synonym

(C) Sequence

(D) Transaction

Ans: A

 

Q.21 The method of access which uses key transformation is known as

(A) Direct

(B) Hash

(C) Random

(D) Sequential

Ans: B

 

Q.22 A table joined with itself is called

(A) Join

(B) Self Join

(C) Outer Join

(D) Equi Join

Ans: B

 

Q.23 _________ data type can store unstructured data

(A) RAW

(B) CHAR

(C) NUMERIC

(D) VARCHAR

Ans: A

 

Q.24 Which two files are used during operation of the DBMS

(A) Query languages and utilities

(B) DML and query language

(C) Data dictionary and transaction log

(D) Data dictionary and query language

Ans: C

Saturday, September 26, 2020

Database Systems MCQ

 Q.1 Which of the following is correct:
(A) a SQL query automatically eliminates duplicates.
(B) SQL permits attribute names to be repeated in the same relation.
(C) a SQL query will not work if there are no indexes on the relations
(D) None of these
Ans: D

Q.2 It is better to use files than a DBMS when there are
(A) Stringent real-time requirements.
(B) Multiple users wish to access the data.
(C) Complex relationships among data.
(D) All of the above.
Ans: B

Q.3 The conceptual model is
(A) dependent on hardware.
(B) dependent on software.
(C) dependent on both hardware and software .
(D) independent of both hardware and software.
Ans: D

Q.4 What is a relationship called when it is maintained between two entities?
(A) Unary
(B) Binary
(C) Ternary
(D) Quaternary
Ans: B

Q.5 Which of the following operation is used if we are interested in only certain columns of a table?
(A) PROJECTION
(B) SELECTION
(C) UNION
(D) JOIN
Ans: A

Q.6 Which of the following is a valid SQL type?
(A) CHARACTER
(B) NUMERIC
(C) FLOAT
(D) All of the above
Ans: D

Q.7 The RDBMS terminology for a row is
(A) tuple.
(B) relation.
(C) attribute.
(D) degree.
Ans: A

Q.8 Which of the following operations need the participating relations to be union compatible?
(A) UNION
(B) INTERSECTION
(C) DIFFERENCE
(D) All of the above
Ans: D

Q.9 The full form of DDL is
(A Dynamic Data Language
(B) Detailed Data Language
(C) Data Definition Language
(D) Data Derivation Language
Ans: C

Q.10 Which of the following is an advantage of view?
(A) Data security
(B) Derived columns
(C) Hiding of complex queries
(D) All of the above
Ans: D

Q.11 Which of the following is a legal expression in SQL?
(A) SELECT NULL FROM EMPLOYEE;
(B) SELECT NAME FROM EMPLOYEE;
(C) SELECT NAME FROM EMPLOYEE WHERE SALARY = NULL;
(D) None of the above
Ans: B

Q.12 The users who use easy-to-use menu are called
(A) Sophisticated end users.
(B) Naïve users.
(C) Stand-alone users.
(D) Casual end users.
Ans: B

Q.13 Which database level is closest to the users?
(A) External
(B) Internal
(C) Physical
(D) Conceptual
Ans: A

Q.14 Which are the two ways in which entities can participate in a relationship?
(A) Passive and active
(B) Total and partial
(C) Simple and Complex
(D) All of the above
Ans: B

Q.15 The result of the UNION operation between R1 and R2 is a relation that includes
(A) all the tuples of R1
(B) all the tuples of R2
(C) all the tuples of R1 and R2
(D) all the tuples of R1 and R2 which have common columns
Ans: D

Q.16 Which of the following is a comparison operator in SQL?
(A) =
(B) LIKE
(C) BETWEEN
(D) All of the above
Ans: D

Q.17 A set of possible data values is called
(A) attribute.
(B) degree.
(C) tuple.
(D) domain.
Ans: D

Q.18 Which of the operations constitute a basic set of operations for manipulating relational data?
(A) Predicate calculus
(B) Relational calculus
(C) Relational algebra
(D) None of the above
Ans:C

Q.19 Which of the following is another name for weak entity?
(A) Child
(B) Owner
(C) Dominant
(D) All of the above
Ans: A

Q.20 Which of the following database object does not physically exist?
(A) base table
(B) index
(C) view
(D) none of the above
Ans: C

Q.21 NULL is
(A) the same as 0 for integer
(B) the same as blank for character
(C) the same as 0 for integer and blank for character
(D) not a value
Ans: D

Q.22 Which of the following is record based logical model?
(A) Network Model
(B) Object oriented model
(C) E-R Model
(D) None of these
Ans: A

Q.23 A data dictionary is a special file that contains:
(A) The name of all fields in all files.
(B) The width of all fields in all files.
(C) The data type of all fields in all files.
(D) All of the above.
Ans: D

Q.24 A file manipulation command that extracts some of the records from a file is called
(A) SELECT
(B) PROJECT
(C) JOIN
(D) PRODUCT
Ans: A

Search Aptipedia