ERD

Question 1

A thing in the real world with an independent existence (house, person

Answer 1

Entity

Question 2

May be an object with physical existence or with a consensual existence (course, job)

Answer 2

Entity

Question 3

Properties that describe the entities

Answer 3

Attributes

Question 4

TYPES OF ATTRIBUTES

Answer 4

Composite attributes
Simple attributes
Single valued attributes
Multivalued attributes
Derived attributes
Stored attributes

Question 5

Can be divided into further parts

Answer 5

Composite attributes

Question 6

Cannot be divided further

Answer 6

Simple attributes

Question 7

Have a single value for a particular entity

Answer 7

Single valued attributes

Question 8

Can have set of values for a particular entity

Answer 8

Multivalued attributes

Question 9

Can be derived from other attributes

Answer 9

Derived attributes

Question 10

From which the value of other attributes are derived

Answer 10

Stored attributes

Question 11

Has multivalued and composite components in it

Answer 11

Complex attributes

Question 12

Multivalued attributes represented within

Answer 12

{ }

Question 13

Composite values represented within

Answer 13

( )

Question 14

Something not applicable or unknown

Answer 14

Null values

Question 15

Collection of entities that have the same attributes

Answer 15

Entity types

Question 16

Collection of entities of a particular entity type at a point in time

Answer 16

Entity set

Question 17

Attribute that is capable of identifying each entity uniquely

Answer 17

Key attribute

Question 18

The set of values that can be assigned to an attribute

Answer 18

Value set of attributes

Question 19

database design process

Answer 19

1. requirements collection and analysis
2. conceptual design
3. logical design (data model mapping)
4. physical design

Question 20

Database designers understand and document the data requirements of the database users

Answer 20

Requirements collection and analysis

Question 21

Consists of user-defined operations

Answer 21

Functional requirements

Question 22

Creating conceptual schema

Answer 22

Conceptual design

Question 23

Concise description of the data requirements and detailed descriptions of the entity types relationships and constraints

Answer 23

conceptual schema

Question 24

Actual implementation of the database, using commercial DBMS

Answer 24

Logical design (data model mapping)

Question 25

The internal storage structures, indexes, access paths are specified

Answer 25

Physical design

Question 26

Do not key attributes of their own

Answer 26

WEAK ENTITY TYPES

Question 27

Identified by relating to another entity type called the identifying or the owner entity type

Answer 27

WEAK ENTITY TYPES

Question 28

Relationship between weak entity type to its owner

Answer 28

Identifying relationship

Question 29

different symbols used in erd

Answer 29

entity weak entity attributes key attribute multivalued attribute composite attribute derived attribute identifying relationship

Question 30

Association among 2 or more entities

Answer 30

Relationship

Question 31

Denotes the number of entity types that participate in a relationship

Answer 31

Degree of relationship

Question 32

degrees of relationship

Answer 32

unary relationship binary relationship ternary relationship

Question 33

relationship constraints

Answer 33

cardinality ration participation constraints

Question 34

maximum number of relationship instances that can entity can participate in (1:1, 1:N, N:1, M:N)

Answer 34

Cardinality ratio

Question 35

specifies whether existence of an entity depends on its being related to another entity

Answer 35

Participation constraints

Question 36

2 types of participation

Answer 36

total participation partial participation

Question 37

attributes of relationship types

Answer 37

1:1 - 1:1 1:N M:N

Question 38

Signifies the role that a participating entirety plays in each relationship instance

Answer 38

Role names

Question 39

Same entity type participates more than once in a relationship type in different roles

Answer 39

Recursive relationships

Question 40

enhanced er model

Answer 40

generalization specialization

Question 41

Bottom up approach where two lower level entities combine to form a higher level entity

Answer 41

Generalization

Question 42

Top down approach where it defines set of subclasses on an entity type

Answer 42

Specialization