CHP 8

Question 1

Conceptual data model?

Answer 1

detailed model that captures the overall structure of organizational data that is independent of any database management system or other implementation considerations

Question 2

E-R Model?

Answer 2

Entity-relationship data model: a detailed logical representation of the entities, associations, and data elements for an organization

Question 3

E-R Diagram?

Answer 3

a graphical representation of an E-R model

Question 4

Entity Type (entity class)

Answer 4

collection of entities that share a common properties/characteristics
Singular noun

Question 5

a single occurrence of an entity type (instance)

Answer 5

Entity Instance

Question 6

Attribute

Answer 6

named property/characteristic of an entity that is of interest to the organization
Noun

Question 7

Candidate Key

Answer 7

attribute/combo of attributes that uniquely identifies each instance of an entity type

Question 8

Identifier

Answer 8

candidate key that has been selected as the unique, identifying characteristic for an entity type

Question 9

Multivalued attribute

Answer 9

an attribute that may take more than one value for each entity instance

Question 10

Repeating group

Answer 10

a set of two or more multivalued attributes that are logically related

Question 11

Required Attribute

Answer 11

attribute that must have a value for every entity instance

Question 12

Optional attribute

Answer 12

attribute that may not have a value for every entity instance

Question 13

Composite attribute

Answer 13

attribute that has meaningful component parts

Question 14

Derived attribute

Answer 14

attribute whose value can be computed from related attribute values

Question 15

Relationships

Answer 15

association between the instance of one or more entity types that is of interest to the organization
verb phrase

Question 16

Degree

Answer 16

of entity types that participate in a relationship

Question 17

Unary Relationship

Answer 17

relationship b/w instances of one entity type; also called recursive relationship

Question 18

Binary relationship

Answer 18

relationship between instances of two entity types. most common in data modeling

Question 19

Ternary relationship

Answer 19

simultaneous relationship among instance of three entity types

Question 20

Cardinality

Answer 20

of instances of entity B that can (or must) be associated with each instance of entity A

Question 21

Associative Entity

Answer 21

entity type that associates the instances of one or more entity types and contains attributes that are peculiar to the relationship between those entity instances

Question 22

Subtype

Answer 22

subgrouping of the entities in an entity type that is meaningful to the organization and that shares common attributes/relationships distinct from other subgroupings

Question 23

Supertype

Answer 23

generic entity type that has a relationship with one or more subtypes

Question 24

Total Specialization rule

Answer 24

specifies that each entity instance of the supertype must be a member of some subtype of the relationship

Question 25

Partial Specialization Rule

Answer 25

specifies that one entity instance of the supertype does not have to belong to any subtype

Question 26

Disjoint Rule

Answer 26

Specifies that if an entity instance of the supertype is a member of one subtype, it cannot simultaneously be a member of any other subtype

Question 27

Overlap Rule

Answer 27

specifies that an entity instance can simultaneously be a member of two or more subtypes

Question 28

Business Rules

Answer 28

specifications that preserve the integrity of the logical data model

Question 29

4 basic business rules

Answer 29

1. Entity Integrity 2. Referential integrity constraints 3. Domains 4. Triggering Opperations

Question 30

Domain

Answer 30

set of all data types and values that an attribute can assume

Question 31

Tiggering Operation (tigger)

Answer 31

assertion or rule that governs the validity of data manipulation operations such as insert, update, and delete (tigger)