Quiz 2 - Ch 4

Question 1

Entity Relationship Model forms the basis of an e….. r…… d……

Answer 1

Entity relationship diagram

Question 2

E…… represents conceptual database as viewed by end user.

Answer 2

ERD

Question 3

ERD depicts the database’s main components: E……., A……, R…….

Answer 3

Entities, attributes, relationships

Question 4

Refers to entity set and not to single entity occurrence: E……

Answer 4

Entities

Question 5

Corresponds to table and not to row in relational environment: E……

Answer 5

Entities

Question 6

In both Chen and Crow’s Foot models, entity is represented by r…….. containing entity’s name

Answer 6

Rectangle

Question 7

Entity name, a noun, is usually written in c……… l…….

Answer 7

capital letters

Question 8

Characteristics of entities: A……….

Answer 8

Attributes

Question 9

R………… a…………. : Must have a value, cannot be left empty

Answer 9

Required attribute

Question 10

O……….. a………….. : Does not require a value, can be left empty

Answer 10

Optional attribute: Does not require a value, can be left empty

Question 11

Attributes have a d………

Answer 11

domain

Question 12

D………… is attribute’s set of possible values

Answer 12

domain

Question 13

Attributes may s…… a domain

Answer 13

share

Question 14

Primary key composed of more than one attribute: C…… k……..

Answer 14

composite key

Question 15

An attribute that can be further subdivided to yield additional attributes : C……… a………

Answer 15

Composite Attribute

Question 16

An attribute that can be further subdivided to yield additional attributes: S……… a……..

Answer 16

Simple Attribute

Question 17

Single-value attribute can have only a s…….. v……..

Answer 17

Single value

Question 18

A single-valued attribute is not necessarily a s…… a…….

Answer 18

simple attribute

Question 19

M…………… a………… can have many values

Answer 19

Multivalued attributes

Question 20

Attribute whose value may be calculated (derived) from other attributes: d…….. a……….

Answer 20

Derived Attributes

Question 21

Need not be physically stored within database: d………. a………..

Answer 21

Derived Attributes

Question 22

Can be derived by using an algorithm: d………. a……….

Answer 22

Derived Attributes

Question 23

Advantages of Storing Derived Attributes
Saves CPU p……….cycle
D…… value is r…….available
Can be used to keep track oh h…….. d……..

Answer 23

Saves CPU processing cycle
Data value is readly available
Can be used to keep track oh historical data

Question 24

Disadvantages of Storing Derived Attributes

Requires constant m…….. ensure d………value is c………, especially if any values used in the c…… change

Answer 24

Requires constant maintenance to ensure derived value is current, especially if any values used in the calculation change

Question 25

Advantages of Non-stored Derived Attributes
Saves s……….. s……,
C…… always yields c…… v………

Answer 25

Saves storage space,

Computation always yields current value

Question 26

Disadvantages of Non-stored Derived Attributes
Uses CPU p……….. c………
Adds coding c……..to q…….

Answer 26

Uses CPU processing cycles

Adds coding complexity to queries

Question 27

Association between entities: R…….

Answer 27

Relationships

Question 28

Association between entities that always operate in both directions: R……

Answer 28

Relationships

Question 29

Entities that participate in a relationship: P……..

Answer 29

Participants

Question 30

Describes the relationship classification (1:1,1:M): C…..

Answer 30

Connectivity

Question 31

Expresses the minimum and maximum number of entity occurrences associated with one occurrence of related entity: C………

Answer 31

Cardinality

Question 32

Entity exists in the database only when it is associated with another related entity occurrence: E….. D…..

Answer 32

Existence dependence

Question 33

Entity exists apart from all of its related entities

Referred to as a strong entity or regular entity: E….. I………

Answer 33

Existence independence

Question 34

Primary key of the related entity does not contain a primary key component of the parent entity : W…….. R……

Answer 34

Weak Relationship (non-identifying)

Question 35

Primary key of the related entity contains a primary key component of the parent entity: S……. R……

Answer 35

Strong Relationships (identifying)

Question 36

Weak entity meets two conditions:
E……..-d…………( Cannot exist without entity with which it has a relationship)
Has p…….. k…… that is partially or totally derived from p……e……..in relationship

Answer 36

Existence-dependent ( Cannot exist without entity with which it has a relationship)
Has primary key that is partially or totally derived from parent entity in relationship

Question 37

One entity occurrence does not require a corresponding entity occurrence in a particular relationship: O……….. P………

Answer 37

Optional Participation

Question 38

One entity occurrence requires a corresponding entity occurrence in a particular relationship: M…….. P……….

Answer 38

Mandatory participation

Question 39

Indicates the number of entities or participants associated with a relationship: R………. D………

Answer 39

Relationship Degree

Question 40

Association is maintained within a single entity

: U………… R……….

Answer 40

Unary Relationship

Question 41

Two entities are associated: B…….. R……..

Answer 41

Binary Relationship

Question 42

Three entities are associated: T………. R……….

Answer 42

Ternary Relationship

Question 43

Also known as composite or bridge entities: A……….. E…………

Answer 43

Associative Entities

Question 44

Used to represent an M:N relationship between two or more entities : A……….. E…………

Answer 44

Associative Entities

Question 45

Is in a 1:M relationship with the parent entities: A……….. E…………

Answer 45

Associative Entities

Question 46

Composed of the primary key attributes of each parent entity: A……….. E…………

Answer 46

Associative Entities