Introduction To Database Questions and Answers

Q: The following are functions of a DBMS except ________ .

Correct answer: creating and processing formsA DBMS creates databases, processes data and provides the tools to administer them - backup, security, concurrency. Forms belong to the application, not to the DBMS: they are the user interface built on top of it. (Products such as Access blur the line by bundling both, which is what makes this question worth asking.)

Q: Cross Product is a:

Correct answer: Binary OperatorThe Cartesian product takes two relations and returns one, so it is a binary operator - as are union, difference, intersection and join. Selection and projection are unary, taking a single relation.

Q: In __________ data can be stored in structured manner.

Correct answer: DatabaseA database stores data in a structured way: organised into tables of typed columns, with keys and defined relationships between them. The CPU and ALU are processing hardware and store nothing of the kind.

Q: What is a relationship called when it is maintained between two entities?

Correct answer: BinaryA relationship’s degree is the number of entity types it connects: binary for two, unary (recursive) for one entity type related to itself, ternary for three. Binary relationships are much the most common.

Q: Database applications are seldom intended for use by a single user.

Correct answer: FalsePlenty of database applications are meant for a single user - a personal contact list, a small stock record, most Access databases. The multi-user case is the harder and more interesting one, but it is not the only one.

Q: 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:

Correct answer: mnA join is a selection applied to the Cartesian product, so it can never return more tuples than the product itself, which has \(m \times n\). That maximum is reached only when the join condition matches every pair - in effect a cross join. A typical equijoin on a foreign key returns far fewer.

Q: Which of the following is another name for weak entity?

Correct answer: ChildA weak entity has no key of its own and depends on an owner for its identity, so it is also called the child or subordinate entity; the entity it depends on is the owner, parent or dominant one. A loan payment identified only by its number within a given loan is the classic example.

Q: The database environment has all of the following components except:

Correct answer: Separate filesThe database environment consists of users, applications, the DBMS, the database and the database administrator. Separate files are precisely what it replaces - the pre-database arrangement, in which each application kept its own file and the same data was duplicated and grew inconsistent.

Q: A DBMS query language is designed to

Correct answer: All of the above.A query language covers all three: ad hoc questions in near-English for end users; the data manipulation that application code is built on; and, through its data definition part, the structure of the database itself. SQL is the obvious example - SELECT, INSERT and CREATE TABLE all belong to it.

Q: SQL stands for ________ .

Correct answer: Structured Query LanguageSQL is Structured Query Language. It came out of IBM’s System R project as SEQUEL and was standardised by ANSI in 1986; it covers not only queries but also data definition, updates and access control.

21.

The following are functions of a DBMS except ________ .

A.creating and processing forms
B.creating databases
C.processing data
D.administrating databases

Answer: A

Correct answer: creating and processing forms

A DBMS creates databases, processes data and provides the tools to administer them - backup, security, concurrency. Forms belong to the application, not to the DBMS: they are the user interface built on top of it. (Products such as Access blur the line by bundling both, which is what makes this question worth asking.)

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22.

Cross Product is a:

A.Unary Operator
B.Ternary Operator
C.Binary Operator
D.Not an operator

Answer: C

Correct answer: Binary Operator

The Cartesian product takes two relations and returns one, so it is a binary operator - as are union, difference, intersection and join. Selection and projection are unary, taking a single relation.

Discuss in Forum

23.

In __________ data can be stored in structured manner.

A.None of these
B.CPU
C.Database
D.ALU

Answer: C

Correct answer: Database

A database stores data in a structured way: organised into tables of typed columns, with keys and defined relationships between them. The CPU and ALU are processing hardware and store nothing of the kind.

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24.

What is a relationship called when it is maintained between two entities?

A.Unary
B.Binary
C.Ternary
D.Quaternary

Answer: B

Correct answer: Binary

A relationship’s degree is the number of entity types it connects: binary for two, unary (recursive) for one entity type related to itself, ternary for three. Binary relationships are much the most common.

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25.

Database applications are seldom intended for use by a single user.

A.True
B.False
C.None of the Above.
D.All of the Above.

Answer: B

Correct answer: False

Plenty of database applications are meant for a single user - a personal contact list, a small stock record, most Access databases. The multi-user case is the harder and more interesting one, but it is not the only one.

Discuss in Forum

26.

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)

Answer: A

Correct answer: mn

A join is a selection applied to the Cartesian product, so it can never return more tuples than the product itself, which has \(m \times n\). That maximum is reached only when the join condition matches every pair - in effect a cross join. A typical equijoin on a foreign key returns far fewer.

Discuss in Forum

27.

Which of the following is another name for weak entity?

A.Child
B.Owner
C.Dominant
D.All of the above

Answer: A

Correct answer: Child

A weak entity has no key of its own and depends on an owner for its identity, so it is also called the child or subordinate entity; the entity it depends on is the owner, parent or dominant one. A loan payment identified only by its number within a given loan is the classic example.

Discuss in Forum

28.

The database environment has all of the following components except:

A.Users.
B.Separate files
C.Database.
D.Database administrator

Answer: B

Correct answer: Separate files

The database environment consists of users, applications, the DBMS, the database and the database administrator. Separate files are precisely what it replaces - the pre-database arrangement, in which each application kept its own file and the same data was duplicated and grew inconsistent.

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29.

A DBMS query language is designed to

A.Support end users who use English-like commands
B.Support in the development of complex applications software
C.Specify the structure of a database.
D.All of the above.

Answer: D

Correct answer: All of the above.

A query language covers all three: ad hoc questions in near-English for end users; the data manipulation that application code is built on; and, through its data definition part, the structure of the database itself. SQL is the obvious example - SELECT, INSERT and CREATE TABLE all belong to it.

Discuss in Forum

30.

SQL stands for ________ .

A.Structured Query Language
B.Sequential Query Language
C.Structured Question Language
D.Sequential Question Language

Answer: A

Correct answer: Structured Query Language

SQL is Structured Query Language. It came out of IBM’s System R project as SEQUEL and was standardised by ANSI in 1986; it covers not only queries but also data definition, updates and access control.

Discuss in Forum

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