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1.

Functional dependencies are a generalization of(a) Key dependencies(b) Relation dependencies(c) Database dependencies(d) None of the mentionedThis question was addressed to me during an online exam.Asked question is from Extended E-R Features in section Database Systems Design and Implementation of Database Management

Answer» CORRECT ANSWER is (a) Key dependencies

The best explanation: The subclasses are COMBINED to form the SUPERCLASS.
Discussion
2.

There are similarities between the instructor entity set and the secretary entity set in the sense that they have several attributes that are conceptually the same across the two entity sets: namely, the identifier, name, and salary attributes. This process is called(a) Commonality(b) Specialization(c) Generalization(d) SimilarityThis question was posed to me in an international level competition.I'd like to ask this question from Extended E-R Features in chapter Database Systems Design and Implementation of Database Management

Answer»

The correct ANSWER is (c) Generalization

For EXPLANATION: Generalization is USED to emphasize the SIMILARITIES among lower-level entity sets and to hide the differences.
Discussion
3.

Which of the following can be used as a primary key entry of the instructor relation.(a) DEPT_NAME(b) NAME(c) ID(d) All of the mentionedI had been asked this question in semester exam.This is a very interesting question from Querying database part-1 DDL in section Database Systems Design and Implementation of Database Management

Answer»

Right answer is (c) ID

Explanation: The value ID can only be primary key UNLIKE dept_name which is used as a FOREIGN key.
Discussion
4.

Identify the error in the section relation(a) No error(b) Year numeric (4,0)(c) Building varchar (15)(d) Sec_id varchar (8)I got this question in semester exam.This question is from Querying database part-1 DDL topic in portion Database Systems Design and Implementation of Database Management

Answer»

Right CHOICE is (a) No error

The best EXPLANATION: The building and the sec_id have VARCHAR values and year is of NUMERIC type. So no such ERRORS are found in the relation.
Discussion
5.

If an entity set is a lower-level entity set in more than one ISA relationship, then the entity set has(a) Hierarchy(b) Multilevel inheritance(c) Single inheritance(d) Multiple inheritanceThe question was asked in unit test.Question is taken from Extended E-R Features in section Database Systems Design and Implementation of Database Management

Answer»

Correct answer is (d) MULTIPLE inheritance

For explanation: The attributes of the higher-level ENTITY SETS are SAID to be inherited by the lower-level entity sets.
Discussion
6.

A _____________ constraint requires that an entity belong to no more than one lower-level entity set.(a) Disjointness(b) Uniqueness(c) Special(d) RelationalI got this question in a job interview.This intriguing question originated from Extended E-R Features topic in chapter Database Systems Design and Implementation of Database Management

Answer»

Right ANSWER is (a) Disjointness

The explanation is: For example, student entity can satisfy only one CONDITION for the student type attribute; an entity can be EITHER a GRADUATE student or an undergraduate student, but cannot be both.
Discussion
7.

The refinement from an initial entity set into successive levels of entity subgroupings represents a ________ design process in which distinctions are made explicit.(a) Hierarchy(b) Bottom-up(c) Top-down(d) RadicalI got this question in an interview for internship.My question comes from Extended E-R Features topic in portion Database Systems Design and Implementation of Database Management

Answer»

Correct ANSWER is (c) Top-down

The explanation is: The DESIGN process may also proceed in a bottom-up MANNER, in which MULTIPLE entity sets are synthesized into a higher-level entity set on the BASIS of common features.
Discussion
8.

Which of the following command is used to display the departments of the instructor relation?(a) Select * from instructor where Dept_name = Finance;(b) Select * from instructor ;(c) Select dept_name from instructor;(d) Select dept_name for instructor where Name=Jackson;This question was posed to me in homework.The above asked question is from Querying database part-2 DML in chapter Database Systems Design and Implementation of Database Management

Answer»

The correct CHOICE is (C) SELECT dept_name from instructor;

The explanation is: Only one field is NECESSARY for the query and where clause is not NEEDED for the selection.
Discussion
9.

Which relationship is used to represent a specialization entity?(a) ISA(b) AIS(c) ONIS(d) WHOISI got this question in unit test.I need to ask this question from Extended E-R Features in section Database Systems Design and Implementation of Database Management

Answer» CORRECT ANSWER is (a) ISA

For EXPLANATION: In terms of an E-R diagram, specialization is depicted by a hollow arrow-head pointing from the SPECIALIZED entity to the other entity.
Discussion
10.

If an attribute of a composite key is dependent on an attribute of the other composite key, a normalizationcalled _____ is needed.(a) DKNF(b) BCNF(c) Fourth(d) ThirdThe question was asked in class test.The question is from Atomic Domains in chapter Database Systems Design and Implementation of Database Management

Answer»

Correct OPTION is (b) BCNF

The EXPLANATION is: BCNF eliminates all redundancy that can be discovered based on FUNCTIONAL DEPENDENCIES.
Discussion
11.

If a relation is in BCNF, then it is also in(a) 1 NF(b) 2 NF(c) 3 NF(d) All of the mentionedI have been asked this question in a national level competition.My doubt stems from Atomic Domains in section Database Systems Design and Implementation of Database Management

Answer» RIGHT choice is (d) All of the mentioned

Best explanation: Third NORMAL form (3NF) relaxes this CONSTRAINT slightly by allowing certain NONTRIVIAL functionaldependencieswhose left side is not a SUPERKEY.
Discussion
12.

A domain is ______ if elements of the domain are considered to be indivisible units.(a) Atomic(b) Subatomic(c) Substructure(d) SubsetThe question was asked by my school teacher while I was bunking the class.My doubt stems from Atomic Domains in portion Database Systems Design and Implementation of Database Management

Answer»

The CORRECT CHOICE is (a) Atomic

Easy EXPLANATION - A set of names is an EXAMPLE of a nonatomic value.
Discussion
13.

Which one is based on multi-valued dependency:(a) First(b) Second(c) Third(d) FourthI had been asked this question during an online interview.This question is from Atomic Domains in chapter Database Systems Design and Implementation of Database Management

Answer»

The CORRECT choice is (d) Fourth

To explain: One of the more desirable NORMAL FORMS that we can OBTAIN is Boyce–Codd normal form (BCNF). It eliminates all redundancy that can be discovered based on functional dependencies.
Discussion
14.

The term for information that describes what type of data is available in a database is:(a) Data dictionary(b) data repository(c) Index data(d) MetadataThe question was posed to me during an interview.My question is from Atomic Domains in chapter Database Systems Design and Implementation of Database Management

Answer» CORRECT CHOICE is (d) Metadata

To explain: META data is GENERALLY data about a data.
Discussion
15.

Consider the employee work-team example, and assume that certain employees participate in more than one work team. A given employee may therefore appear in more than one of the team entity sets that are lower level entity sets of employee. Thus, the generalization is _____________(a) Overlapping(b) Disjointness(c) Uniqueness(d) RelationalThis question was posed to me in an interview for internship.This is a very interesting question from Extended E-R Features in portion Database Systems Design and Implementation of Database Management

Answer» RIGHT option is (a) Overlapping

Easiest EXPLANATION - In overlapping GENERALIZATIONS, the same ENTITY may belong to more than one lower-level entity set within a SINGLE generalization.
Discussion
16.

In the section relation which of the following is used as a foreign key?(a) Course_id(b) Course_id,sec_id(c) Room_number(d) Course_id,sec_id,room_numberThe question was posed to me during an online interview.My query is from Querying database part-1 DDL topic in chapter Database Systems Design and Implementation of Database Management

Answer»

Right choice is (a) Course_id

Easiest explanation - Course_id is the only field which is PRESENT in the COURSE RELATION.
Discussion
17.

In the above DDL command the foreign key entries are got by using the keyword(a) References(b) Key reference(c) Relating(d) None of the mentionedThis question was posed to me in semester exam.I'd like to ask this question from Querying database part-1 DDL topic in chapter Database Systems Design and Implementation of Database Management

Answer»

Right ANSWER is (a) REFERENCES

Explanation: References (table_name) give the prior table name for the ENTRY.
Discussion
18.

A data type that creates unique numbers for key columns in Microsoft Access is:(a) Autonumber(b) Boolean(c) Sequential key(d) Sequential numberThis question was addressed to me during an interview.My question is from Atomic Domains topic in portion Database Systems Design and Implementation of Database Management

Answer» CORRECT option is (a) Autonumber

To EXPLAIN: This can be taken as a primary KEY.
Discussion
19.

In the course relation, the title field should throw an error in case of any missing title. The command to be added in title is(a) Unique(b) Not null(c) 0(d) NullI have been asked this question in semester exam.This intriguing question comes from Querying database part-1 DDL in portion Database Systems Design and Implementation of Database Management

Answer»

The CORRECT answer is (b) Not NULL

Easy explanation - By SPECIFYING not null the VALUE cannot be left blank.
Discussion
20.

If every non-key attribute is functionally dependent primary key, then the relation will be in(a) First normal form(b) Second normal form(c) Third form(d) Fourth normal formThis question was addressed to me in unit test.The origin of the question is Atomic Domains topic in chapter Database Systems Design and Implementation of Database Management

Answer»

Correct option is (b) Second NORMAL form

Easy explanation - THIRD normal form (3NF) relaxes this constraint slightly by ALLOWING certain nontrivial functionaldependencieswhose left SIDE is not a SUPERKEY.
Discussion
21.

Identify the composite attributes(a) Salary(b) Credits(c) Section_id(d) None of the mentionedI got this question by my college professor while I was bunking the class.I need to ask this question from Atomic Domains in portion Database Systems Design and Implementation of Database Management

Answer» CORRECT OPTION is (d) None of the mentioned

Explanation: Composite attributes, such as an attribute address with COMPONENT attributes street, CITY, state, and ZIP have nonatomic domains.
Discussion
22.

The completeness constraint may be one of the following: Total generalization or specialization, Partial generalization or specialization. Which is the default?(a) Total(b) Partial(c) Should be specified(d) Cannot be determinedThis question was posed to me in exam.My enquiry is from Extended E-R Features topic in section Database Systems Design and Implementation of Database Management

Answer» CORRECT choice is (b) PARTIAL

For EXPLANATION: Partial GENERALIZATION or specialization – Some higher-level ENTITIES may not belong to any lower-level entity set.
Discussion
23.

In order to include an attribute Name to the teaches relation which of the following command is used?(a) Alter table teaches include Name;(b) Alter table teaches add Name;(c) Alter table teaches add Name varchar;(d) Alter table teaches add Name varchar(20);I had been asked this question in an international level competition.The question is from Querying database part-1 DDL in section Database Systems Design and Implementation of Database Management

Answer» RIGHT choice is (d) ALTER table teaches add Name varchar(20);

Easy explanation - The form of the alter table command is

alter table r add AD;

where r is the name of an existing relation, A is the name of the attribute to be ADDED, and D is the type of the added attribute.
Discussion
24.

The department relation has the an entry budget whose type has to be replaced by(a) Varchar (20)(b) Varchar2 (20)(c) Numeric (12,2)(d) NumericI had been asked this question by my school principal while I was bunking the class.The doubt is from Querying database part-1 DDL in division Database Systems Design and Implementation of Database Management

Answer»

The CORRECT option is (C) NUMERIC (12,2)

Best explanation: Department is the only relation which forms the main part of the university DATABASE.
Discussion
25.

Which is the main relation which is used in the university database which is referenced by all other relation of the university?(a) Teaches(b) Course(c) Department(d) SectionI have been asked this question during an interview.I'm obligated to ask this question of Querying database part-1 DDL in chapter Database Systems Design and Implementation of Database Management

Answer»

Correct ANSWER is (C) Department

To EXPLAIN: Department is the only relation which forms the main part of the university DATABASE.
Discussion
26.

A window into a portion of a database is(a) Schema(b) View(c) Query(d) Data dictionaryThe question was posed to me in homework.The origin of the question is Entity-Relationship Design Issues in division Database Systems Design and Implementation of Database Management

Answer» CORRECT answer is (b) VIEW

The best explanation: View is a logical portion of a DATABASE which is needed by some USERS.
Discussion
27.

The entity relationship set is represented in E-R diagram as(a) Double diamonds(b) Undivided rectangles(c) Dashed lines(d) DiamondI got this question in a job interview.My query is from Entity-Relationship Diagrams topic in section Database Systems Design and Implementation of Database Management

Answer»

Right choice is (d) Diamond

Easiest EXPLANATION - Dashed LINES link ATTRIBUTES of a RELATIONSHIP SET to the relationship set.
Discussion
28.

Which one of the following uniquely identifies the elements in the relation?(a) Secondary Key(b) Primary key(c) Foreign key(d) Composite keyI got this question in semester exam.The above asked question is from Constraints topic in section Database Systems Design and Implementation of Database Management

Answer»

The CORRECT option is (b) Primary key

Explanation: Primary key CHECKS for not NULL and UNIQUENESS constraint.
Discussion
29.

Establishing limits on allowable property values, and specifying a set of acceptable, predefined options that can be assigned to a property are examples of:(a) Attributes(b) Data integrity constraints(c) Method constraints(d) Referential integrity constraintsThis question was posed to me in an interview for internship.The origin of the question is Constraints in portion Database Systems Design and Implementation of Database Management

Answer»

The correct option is (B) Data integrity constraints

For explanation: Only PARTICULAR VALUE satisfying the constraints are ENTERED in the COLUMN.
Discussion
30.

Which of the following is a low level operator?(a) Insert(b) Update(c) Delete(d) DirectoryThe question was posed to me in an internship interview.The query is from Entity-Relationship Design Issues in chapter Database Systems Design and Implementation of Database Management

Answer»

Correct OPTION is (d) DIRECTORY

Best explanation: Directory is a LOW level to word on in file system.
Discussion
31.

Weak entity set is represented as(a) Underline(b) Double line(c) Double diamond(d) Double rectangleI got this question in an international level competition.This question is from Entity-Relationship Diagrams in chapter Database Systems Design and Implementation of Database Management

Answer» RIGHT option is (c) Double diamond

Explanation: An entity SET that has a PRIMARY KEY is termed a strong entity set.
Discussion
32.

Which of the following can be addressed by enforcing a referential integrity constraint?(a) All phone numbers must include the area code(b) Certain fields are required (such as the email address, or phone number) before the record is accepted(c) Information on the customer must be known before anything can be sold to that customer(d) Then entering an order quantity, the user must input a number and not some text (i.e., 12 rather than ‘a dozen’)I have been asked this question by my school principal while I was bunking the class.Origin of the question is Constraints topic in chapter Database Systems Design and Implementation of Database Management

Answer» CORRECT option is (c) INFORMATION on the customer must be KNOWN before anything can be sold to that customer

To explain: NONE.
Discussion
33.

Which of the following indicates the maximum number of entities that can be involved in a relationship?(a) Minimum cardinality(b) Maximum cardinality(c) ERD(d) Greater Entity CountThe question was asked during an internship interview.My question comes from Entity-Relationship Design Issues in portion Database Systems Design and Implementation of Database Management

Answer» CORRECT ANSWER is (b) MAXIMUM cardinality

Easy explanation - In SQL (Structured Query Language), the term cardinality refers to the uniqueness of data values contained in a particular column (ATTRIBUTE) of a database table.
Discussion
34.

The total participation by entities is represented in E-R diagram as(a) Dashed line(b) Double line(c) Double rectangle(d) CircleThis question was posed to me during an online exam.Query is from Entity-Relationship Design Issues in section Database Systems Design and Implementation of Database Management

Answer»

Correct answer is (B) Double line

The best I can explain: It is USED to represent the RELATION between SEVERAL attributes.
Discussion
35.

Which of the following can be a multivalued attribute?(a) Phone_number(b) Name(c) Date_of_birth(d) All of the mentionedThis question was posed to me in my homework.Query is from The Entity-Relationship Model in section Database Systems Design and Implementation of Database Management

Answer»

Right answer is (a) Phone_number

To explain: NAME and Date_of_birth cannot hold more than 1 VALUE.
Discussion
36.

For a weak entity set to be meaningful, it must be associated with another entity set, called the(a) Identifying set(b) Owner set(c) Neighbour set(d) Strong entity setI have been asked this question in an internship interview.The origin of the question is Entity-Relationship Diagrams topic in division Database Systems Design and Implementation of Database Management

Answer»

Right option is (a) IDENTIFYING set

For EXPLANATION: Every weak ENTITY must be associated with an identifying entity; that is, the weak entity set is said to be existence dependent on the identifying entity set. The identifying entity set is said to own the weak entity set that it identifies. It is also called as owner entity set.
Discussion
37.

An entity set that does not have sufficient attributes to form a primary key is termed a __________(a) Strong entity set(b) Variant set(c) Weak entity set(d) Variable setThe question was posed to me during an online interview.I would like to ask this question from Entity-Relationship Diagrams in section Database Systems Design and Implementation of Database Management

Answer» CORRECT OPTION is (C) Weak ENTITY set

For explanation: An entity set that has a primary key is termed a strong entity set.
Discussion
38.

The function that an entity plays in a relationship is called that entity’s _____________(a) Participation(b) Position(c) Role(d) InstanceThe question was asked in exam.Origin of the question is The Entity-Relationship Model in section Database Systems Design and Implementation of Database Management

Answer»

The CORRECT CHOICE is (c) Role

Best explanation: A relationship is an ASSOCIATION AMONG SEVERAL entities.
Discussion
39.

The entity set person is classified as student and employee. This process is called _________(a) Generalization(b) Specialization(c) Inheritance(d) Constraint generalizationI got this question in an online quiz.The doubt is from Extended E-R Features in section Database Systems Design and Implementation of Database Management

Answer»

The CORRECT option is (b) Specialization

For explanation: The process of DESIGNATING subgroupings WITHIN an entity SET is called specialization.
Discussion
40.

Drop Table cannot be used to drop a table referenced by a _________ constraint.(a) Local Key(b) Primary Key(c) Composite Key(d) Foreign KeyThis question was addressed to me in class test.This intriguing question originated from Constraints in section Database Systems Design and Implementation of Database Management

Answer» RIGHT choice is (d) Foreign Key

Explanation: Foreign key is used when primary key of ONE RELATION is used in ANOTHER relation.
Discussion
41.

In E-R diagram generalization is represented by(a) Ellipse(b) Dashed ellipse(c) Rectangle(d) TriangleI had been asked this question in class test.This intriguing question originated from Entity-Relationship Design Issues topic in division Database Systems Design and Implementation of Database Management

Answer»

The CORRECT OPTION is (d) Triangle

Easiest explanation - ELLIPSE represents ATTRIBUTES, rectangle represents entity.
Discussion
42.

Given the basic ER and relational models, which of the following is INCORRECT?(a) An attribute of an entity can have more than one value(b) An attribute of an entity can be composite(c) In a row of a relational table, an attribute can have more than one value(d) In a row of a relational table, an attribute can have exactly one value or a NULL valueThe question was asked in an interview for job.The question is from Entity-Relationship Design Issues topic in division Database Systems Design and Implementation of Database Management

Answer» CORRECT ANSWER is (C) In a row of a relational table, an attribute can have more than one value

Easiest EXPLANATION - It is possible to have several values for a single attribute provide it is a multi-valued attribute.
Discussion
43.

Let us consider phone_number ,which can take single or several values . Treatingphone_numberas an _________ permits instructors to have several phone numbers (including zero) associated with them.(a) Entity(b) Attribute(c) Relation(d) ValueThe question was posed to me in a national level competition.This interesting question is from Entity-Relationship Design Issues topic in division Database Systems Design and Implementation of Database Management

Answer» CORRECT option is (a) Entity

Easiest explanation - TREATING a PHONE as an attribute phone_number implies that instructors have precisely one phone NUMBER each.
Discussion
44.

We indicate roles in E-R diagrams by labeling the lines that connect ___________ to __________(a) Diamond , diamond(b) Rectangle, diamond(c) Rectangle, rectangle(d) Diamond, rectangleThe question was posed to me in my homework.Question is taken from Entity-Relationship Diagrams in section Database Systems Design and Implementation of Database Management

Answer»

Right choice is (d) Diamond, rectangle

For explanation: Diamond REPRESENTS a RELATIONSHIP SET and rectangle represents a entity set.
Discussion
45.

Which of the following is a single valued attribute(a) Register_number(b) Address(c) SUBJECT_TAKEN(d) ReferenceI had been asked this question in an interview for internship.Asked question is from The Entity-Relationship Model in portion Database Systems Design and Implementation of Database Management

Answer» CORRECT CHOICE is (a) Register_number

For EXPLANATION: NONE.
Discussion
46.

The attribute name could be structured as an attribute consisting of first name, middle initial, and last name. This type of attribute is called(a) Simple attribute(b) Composite attribute(c) Multivalued attribute(d) Derived attributeI have been asked this question in an internship interview.My query is from The Entity-Relationship Model topic in division Database Systems Design and Implementation of Database Management

Answer» RIGHT ANSWER is (b) Composite attribute

Easy EXPLANATION - Composite attributes can be DIVIDED into subparts (that is, other attributes).
Discussion
47.

The Rectangles divided into two parts represents(a) Entity set(b) Relationship set(c) Attributes of a relationship set(d) Primary keyThe question was posed to me in an interview for job.The above asked question is from Entity-Relationship Diagrams topic in section Database Systems Design and Implementation of Database Management

Answer»

The correct option is (a) Entity set

To EXPLAIN: The first PART of the RECTANGLE, contains the name of the entity set. The second part contains the NAMES of all the attributes of the entity set.
Discussion
48.

Data integrity constraints are used to:(a) Control who is allowed access to the data(b) Ensure that duplicate records are not entered into the table(c) Improve the quality of data entered for a specific property(d) Prevent users from changing the values stored in the tableI had been asked this question in homework.This intriguing question originated from Constraints topic in chapter Database Systems Design and Implementation of Database Management

Answer»

The correct choice is (c) IMPROVE the QUALITY of data entered for a SPECIFIC property

Best EXPLANATION: The data entered will be in a particular CELL (i.e., table column).
Discussion
49.

The attribute AGE is calculated from DATE_OF_BIRTH. The attribute AGE is(a) Single valued(b) Multi valued(c) Composite(d) DerivedThe question was asked by my college director while I was bunking the class.Query is from The Entity-Relationship Model in portion Database Systems Design and Implementation of Database Management

Answer» RIGHT choice is (d) DERIVED

The explanation is: The VALUE for this TYPE of attribute can be derived from the values of other related attributes or entities.
Discussion
50.

The descriptive property possessed by each entity set is _________(a) Entity(b) Attribute(c) Relation(d) ModelThis question was addressed to me in semester exam.The doubt is from The Entity-Relationship Model topic in portion Database Systems Design and Implementation of Database Management

Answer»

Right option is (b) Attribute

Best explanation: Possible ATTRIBUTES of the instructor ENTITY SET are ID, name, DEPT name, and salary.
Discussion