Geog 495: GIS Database Design

10/19/05

UML Class Diagram

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Object:

Class:

Class is a template for instantiation of objects

Class Diagram is composed of classes and relationships

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Class

Attribute

<<sterotype>>_opt visibility_opt name multiplicity_opt : type_opt = initial-value_opt {property-string}_opt

What is visibility?

What is scope?

Operation

<<sterotype>>_opt visibility_opt name(parameter-list) : return-type_opt {property-string}_opt

e.g.

+ getX(): double

+ setX(newX: double)

The concepts of visibility and scope are applied to operation too.

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Relationships

Multiplicity

Number of participants (classes) involved in an association

Navigability

Direction of navigation between classes

Implementation concept

class Quiz{

// A list of questions

Question [] questions;

....

}

Role name

Constraints

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Class diagram can be created from three different perspectives

• Conceptual: describes problem domain; employed under the analysis
• Specification: not tied to software implementation; employed under design
• Implementation: reflect class to be implemented

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Lab

Here’s a business rule and details of classes to be implemented

Draw UML diagram

Class Information

Course has attribute {name, id}, and operation {getDescription}

Section has attribute {time, semester, cancelled}, and operation {cancel}

CourseSchedule has attribute {semester}, and operation {enroll}

Student has attribute {name, major}, and operation {planSemester}

Coop has attribute {semester}, and operation {getCompany}

where all attributes can be accessed by only the class containing attributes while all operations can be accessed by all classes

Relationship Information

Course may has section or multiple Sections

CourseSchedule is associated with Section only if section is not cancelled

Student look up CourseSchedule

Student live at Coop

Coop is operated by Company