Lect Relationships

8/13/2019 Lect Relationships

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CONCEPTUAL DESIGN:

UML CLASS DIAGRAMRELATIONSHIPS


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1. Identify the information systems purpose

2. Identify the information systems actors and features

3. Identify Use Cases and create a Use Case Diagram

4. Identify Objects and their Classes and create a Class Diagram

5. Create Interaction/Scenario Diagrams

6. Create Detail Logic for Operations

7. Repeat activities 1-6 as required to refine the blueprints

A Simpl i f ied Object-Oriented

Systems Analysis & Conceptual Design Methodology

Activities


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Ob jects have three responsib i l it ies:

What they know about themselves (e.g., A ttr ibutes)

What they do (e.g., Operations )

What they know abou t other objects (e.g., Relation sh ips )

Objects


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Defin ing Class

A CLASS is a template (specif icat ion, blueprint)

for a col lect ion o f objects that share a commonset of attr ibu tes and operat ions .

HealthClubMember

Class

Objects

attr ibutesoperat ions


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Relat ionships

A RELATIONSHIP is what a class or an objec t

knows about another class o r object .

General izat ion (Class-to-Class ) (Superclass/Subclass)

Inh eritance

Ex: Perso n - Faculty Person , StudentPerson, Staff...

Ex: ModesOfTravel - Airp lane, Train, Auto, Cyc le, Boat...

[Object ] Associat ions

Facul tyInformation - Cours eInform at ion

StudentInform ation - Cou rseInform at ion

[Object]Agg regat ions & Compos i tion(Whole-Part)

Assembly - Parts

Group - Members

Container - Contents


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Relat ionsh ips

1) show relat ionships 2) enforce integr i ty 3) help produc e results

Removal of a Univers i ty

Course should also

remove Students that are

in the Course but not

Student Inform at ion.

Removal of a Student

shou ld also remov e the

Courses that the Student

is in but no t the Universi tyCourse.

Removal of a Student in

a Cours e should not af fect

e i ther Univers i ty Cou rse or

Student Inform at ion.

1

0,m

UniversityCourse

StudentInCourse

StudentInformation

1

0,m

Exist to:

In th is examp le:


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UML Class Diagram Notat ion

Member

memberNumber

firstNamelastName

telephone

address

city

etc...

checkOutVideocheckInVideo

buyItem

etc...

attributes

operations

{{

Expanded view of aClass into its three

sections:

Top: Class Name

Middle: attributes

Bottom: operations

Class

1 of 2


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Object Association

n n

ClassGeneralization

Relationship

Object

Aggregation

Association

0..*

1..*

Object

Composition

Association

0..*

1

UML Class Diagram Notat ion 2 of 2

Will always be 1


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Class Diagram Relat ionsh ips

Class

General ization

Object

Associat ion

Aggregat ion

Composi t ion


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Generalization (Class-to-Class) (superc lass sub class; super types ubtype)

A Generalization follows a is a or is a kind of heuristic from a

specialization class to the generalization class. (e.g., student is a

person, video is a kind of inventory). Common attributes, operations and relationships are located in the

generalization class and are inherited by the specialization classes

Unique attributes, operations and relationships are located in the

specialization classes.

Inherited attributes and operations may be overridden or enhanced in

the specialization class depending on programming language

support.

Inherited operations in the specialization classes may be

polymorphic. Only use when objects do NOT transmute (add, copy, delete)

Multiple inheritance is allowed in the UML but can complicate the

class models understanding and implementation (e.g., C++ supports

but Java and Smalltalk do not).


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Person

attributes

operations

Poor General izat ion Example

(violates the is a or is a kind of heuristic)

Arm

attributes

operations

Leg

attributes

operations

Head

attributes

operations


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General izat ion - Mu lt ip le Inheritance

Generalization1

a1a2

a3

o3

o4

o5

Specialization

a6

a7

a8

o6

o7

o8

Generalization2

a2a4

a5

o1

o2

o3

inherited attributes

a1

a2 (which one?)a3

a4

a5

inherited operations

o1

o2

o3

o4

o5

(which one?)


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UML General izat ion Notat ion

Supertype

Subtype 2Subtype 1

discriminator

Useful text

Note

Note: Supertype = Superclass; Subtype = Subclass


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General izat ion - Mu lt ip le Class if icat ion

Person

Female

Male

Physical-therapist

Nurse

Doctor

role

Patient

patient

Gender

{complete}

Discriminator

#1

#2

#3


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230Rational Rose Class Diagram Examp le


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Assoc ia t ions

Relationships between instances (objects)

of classes

Conceptual:

associations can have two roles (bi-directional):

source --> target target --> source

roles have multiplicity (e.g., cardinality,

constraints)

To restrict navigation to one direction only, anarrowhead is used to indicate the navigation

direction

No inheritance as in generalizations

Obj A i i R l i hi P


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x

x

x

x

x

x

Whole

attributes

operations

PartN

attributes

operations

Part2attributes

operations

Part1

attributes

operations

1

y

1

y

1

y

Whole

attributes

operations

PartN

attributes

operations

Part2attributes

operations

Part1

attributes

operations

Class Aattributes

operations

Class B

attributes

operations

Class A

attributes

operations

Class B

attributes

operations

x

x

x

x

Object Association Relationship Patterns

a) Object Associations

b) Object

Aggregation

Associations

c) Object

Composition

Associations(y may not be 1)


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Assoc ia t ions

Class A Class Brole A

role B

Company PersonEmployer

Employee

Example:


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Mult ip l ic i t ies

Class

Class

Class

Class

1

0..*

0..1

m..n

exactly one

many

(zero or more)

optional(zero or one)

numerically

specified

Course CourseOffering

1

0..*

Example:


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Agg regat ion & Compos i tion

Agg regation (shared agg regation ):

is a special ized fo rm of ASSOCIATION in whicha whole is related to its part(s).

is known as a part of or containment

relationship and follows the has a heuristic

three ways to think abou t agg regat ions:

who le-parts

con tainer-con tents

group-members

Compos i t ion (compos i te agg regat ion ):

is a s tron ger version of AGGREGATION

the part(s) may belong to only ONE whole

the part(s) are usually expected to live and

die with the whole (cascading delete)

Aggregation vs. Composi t ion vs. Associat ion???


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Aggregation Composition

0..*

1..*

Faculty

CourseTeaching

1..*

1

SalesOrder

SalesOrderLineItem

(another: hand --> finger)(another: assembly --> part)

(team-teaching

is possible)


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Composi t ion

Person{abstract}

Faculty Student

FacultyStudent

Person

Note: Attributes may need to be considered to more-fully understand

FacultyRole

StudentRole

1

10..1

0..1

Composi t ion is often used in place ofGeneralization (inheritance) to avoid transmuting(adding, copy ing, and delet ing o f ob jects)


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Assoc iat ion, Aggregat ion and Composi t ion

Whole

Part

Whole

Part

0..*

0..*

w

1w

2 w

3w

4

p

6p

4

p

5p

3p

1

p

2

Template/Pattern Example

(assoc iation, aggregat ion &

composi t ion look the same)


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Mult ipl ic i ty Example #2

1..n

1

0..*

2..5

C1

C2

C2

C2

C2

C2

etc...

min.max.

C1

C3

C3

C3

C3

C3

etc...

C3

C1

C1

C1

C1

C11..n * 2..5

Class1

Class2 Class3

C2

C11


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FacultyInformation

1

0..*

1 11

1..* 0..*

0..*

0..*

Mult ipl ic i ty Example #3

StudentInformation

DegreeHeld CommitteeAssign

CourseTeach ClubMember

CourseCompleted

0..*

man t man m ltiplicit


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CourseInformation0..*

0..*

many-to-many multiplicity

attributes

operations

StudentInformation

attributes

operations

Becomes either

0..* 0..*

SemesterTaken

GradeEarned

1 1

StudentInformation

attributes

operations

CourseInformation

attributes

operations

StudentCourseInformation

operations

Attr ibutes that

represent the

union of the

two classes are

located in th is

association

class.

StudentInformation

attributes

operations

CourseInformation

attributes

operations

0..*

0..*

SemesterTaken

GradeEarned

StudentCourseInformation

operations


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Ref lexive Association Relat ionships

Objects with in the same class have a

relat ionsh ip w ith each other.

Course

0..*

0..*

has pre-requisite of

Video Store UML Class Diagram


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Inventory

Video Store UML Class Diagram

SaleItem RentalItem

Video Game ConcessionItem VCR

Transaction Employee StoreLocation

SaleTransaction RentalTransaction Suplier

Member PurchaseOrder

SaleRentalLineItemPurchaseOrderLineItem

1

0..*

0..* 0..1 10..*

1..*

1 1

1..*

10..*

10..*

11..*

10..*

0..*

1


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