97 CONCEPTUAL DESIGN: AN OVERVIEW OF METHODOLOGIES, MODELS AND NOTATIONS.

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CONCEPTUAL DESIGN:

AN OVERVIEW OF

METHODOLOGIES,

MODELS AND NOTATIONS

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Planning & Feasibility Study (optional)

Analysis - Requirements Determination

Design - Conceptual &

Physical

Construction (Purchase) & Testing

Implementation including Training &

Conversion

Evolution - Maintenance &

Enhancements

SYSTEMS DEVELOPMENT LIFE CYCLE (SDLC)ID

S-

306/6

95

IDS

-406/6

97

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METHODOLOGY OVERVIEW

Methodology defined: The way something gets done. (i.e., The strategy, steps, directions, or actions.)

Methodologies can be: purchased created combination of both

Thousands available for developing software-intensive information systems

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SDLC versus Methodology

M #1 M #2…

SDLC =“GenericWay”

Methodology =“Specific Ways”

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METHODOLOGY OVERVIEW

Classifications of Methodologies Traditional Structured Analysis and Design Information Modeling/Engineering

Object-Oriented Prototyping is a technique - (some

say that it is a methodology)

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The Traditional Methodology

Applicable for small teams on small projects

Functional perspective of a problem domain

It is an informal, unstructured, unrepeatable,

un-measurable, ad-hoc way

Tools used to support it are adequate (okay)

(1950s - now)

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Traditional Methodology Tools

-----------TECHNIQUES & TOOLS REPRESENTING-----------System Data ProcessFlows Logic _

Forms,

Layouts,

Grid Charts

System

Flowcharts

English Narrative,

Playscript,

Program Flowcharts,

HIPO Charts

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Structured Analysis and Design Methodology

Data Flow methodology (synonym) Compliments Structured Programming Very popular - perhaps the leading one for business Can be repeatable, measurable, & automated IDE & CASE s/w tools brought significant assistance 1) Yourdon, and 2) Gane & Sarson Functional perspective of a problem domain Describes the real world as data flowing through

the information system, being transformed from inputs to outputs

(mid-1970s - now)

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Structured Analysis and Design Methodology Tools


Data Dictionary,

Data Structure

Diagrams,

Entity-

Relationship

Diagrams

Data Flow

Diagram

Decision Tree/Table,

Structured English,

Structure Charts,

Warnier/Orr Diagram

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Reconcile Account Balances

Pay a

Bill

Withdraw Funds from an Account

Deposit Funds into an Account

Bank

Creditor

Employer

Other Income Source

Bank

Monthly Account Statements

Account Transactions

Bank Accounts

Account Transactions

Bill

Payment

Monthly Statement

Account Balance

Transaction

Prior Monthly Statement

New or Modified Monthly Statement

Modified Balance

Pay

Reimbursement

Withdraw or transfer

Deposit

Payment

Modified Balance

Current Balance

(adapted from Systems Analysis andDesign Methods, 4th Edition, Whittenand Bentley, McGraw-Hill, 1998)

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(adapted from Systems Analysis andDesign Methods, 4th Edition, Whittenand Bentley, McGraw-Hill, 1998)

CUSTOMER

Customer Number (PK) Customer Name Shipping Address Billing Address Balance Due

ORDER

Order Number (PK) Order Date Order Total Cost Customer Number (FK)

INVENTORY PRODUCT

Product Number (PK) Product Name Product Unit of Measure Product Unit Price

ORDERED PRODUCT

Ordered Product ID (PK) . Order Number (FK) . Product Number (FK) Quantity Ordered Unit Price at Time of Order

has placed

sold

sold as

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Information Modeling Methodology

Data modeling & information engineering

(synonyms)

Describes the real world by its data, the

data’s attributes, and the data relationships

Can be repeatable, measurable, and

automated

Data perspective of the problem domain

(early-1980s - now)

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Information Modeling Methodology Tools


Business

Area

Analysis,

Entity-

Relationship

Diagrams

Business

Area

Analysis,

Process

Model

Business Systems

Design

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Object-Oriented Methodology

Object modeling

Compliments object-oriented programming

Can be repeatable, measurable, & automated

Object perspective of the problem domain

Describes the real world by its objects, the

attributes, operations, and relationships

Data & functions are encapsulated together

(mid/late-1980s - now)

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Object-OrientedMethodology Tools


Object Model

Attributes

Object

Model

Static & Dynamic UML

Model Diagrams,

Operations,

Class relationships,

Object associations

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Object-Oriented Methodology

Revolutionary or Evolutionary?

Most difficult aspect is the transition some

people have to make from a functional or

data problem solving strategy to an object

problem solving strategy. Some people

must change from a “function think” or

“data think” to an “object think” strategy.

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Rational Corporation’s Rational Unified Process

(RUP)

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Object Technology Principles

Common Methods of Organization

Abstraction

Encapsulation (Information

Hiding)

Inheritance

Polymorphism

Message Communication

Associations

Reuse

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Objects and their characteristicsObjects and their characteristics

Wholes and PartsWholes and Parts

Groups (Classes) and MembersGroups (Classes) and Members

Classification Theory(Common Methods of Organization)

O-O Systems Analysis & Design Methodology

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• Common Methods of Organization

People are accustomed to thinking in terms

of...

• color• price• weight• engine• options...

Objects & Attributes

• number of doors• number of wheels• number of windows• number of lights• number of bolt type 1• number of bolt type 2• etc....

Wholes and PartsGroups & Members

VANS:• light utility• utility• passenger• etc...

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• AbstractionA mental ability that permits people to view real-world

problem domains with varying degrees of detail depending on the current context of the problem.

• Helps people to think about what they are doing• Functional and Data abstraction

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• Encapsulation (Information Hiding)

A technique in which data are packaged

together with their corresponding procedures.

cakeIngredients

Directions

2 eggs 4 cups flour1 cup milk 1 cup sugaretc.......

Pre-heat oven to 350; Putmilk, eggs, and sugarin 2 quart mixing bowl...

In Object-Oriented Technology the “package” is called an In Object-Oriented Technology the “package” is called an OBJECTOBJECT

The interface to each object is defined in such a way as to reveal as The interface to each object is defined in such a way as to reveal as

little as possible about its inner workingslittle as possible about its inner workings

Encapsulation allows [software] changes to be reliably made with Encapsulation allows [software] changes to be reliably made with

limited effort [Gannon, Hamlet, & Mills, 1987]limited effort [Gannon, Hamlet, & Mills, 1987]

One cake please!

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• InheritanceA mechanism for expressing similarity

between things thus simplifying their

definition.

• looks• behavior• attitudes• etc...

Person

Student Faculty Staff

Inheritance

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• Polymorphism (“many forms”)

The ability to hide different implementations

behind a common interface.

The ability for two or more objects to respond

to the same request, each in its own way.

H O = water, ice, steam (liquid, solid, vapor) Eating Carbon compound crystallizes as graphite & diamond

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versusDoor#1

Door#2

Door#3

Door#1#2#3

• Polymorphism Two examples

PRINT0

5000

10000

15000

20000

25000

North

Sout

h

East

Wes

t

B L U E S K Y A I R L I N E SSales ReportJanuary

B L U E S K Y A I R L I N E SSales ReportFebruary

PRINT

PRINT

TEXT object

GRAPH object

IMAGE object

Object #1 PO object

Account object

Department object

Object #2

Object #3

Add

Add

Add

= add a line item to the PO

= increase $ Amount Balance

= hire a new employee

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• Message Communication

OBJECT

OBJECT

OBJECT

OBJECT

Objects communicate via messages

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• AssociationsThe union or connection of ideas or things.

(Objects need to interact with each other)

• same point in time

Billing StatementAdvertisement #1Advertisement #2

• under similar circumstances

crimescene

#1

crimescene

#2

crimescene

#n

Person

Student Faculty Staff

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• Reuse

Varying Degrees of Reuse:

• complete or sharing

• copy, purchase or cloning

• partial or adjusting

• none

The ability to reuse objects

Software:• “Chips”• Components• Controls• Models

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• Reuse

• Components must be reused three to five times before the costs of creating and supporting them are recovered• It costs one and a half to three times as much to create and support a single reusable component as to create a component for just one use• It costs 25% as much to use a reusable component as it does to create a new one• It takes two to three product cycles (about three years) before the benefits of reuse become significant

Software Reuse Costs and PayoffsOrenstein, D. “Code reuse: Reality doesn’t match promise”,

Computerworld, August 24, 1998, page 8.

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O-O Systems Analysis & Design Methodology

Three Classic Systems Analysis and Design Challenges:

Data Model versus Function ModelData Model versus Function Model

Analysis to Design TransitionAnalysis to Design Transition

Maintaining Source CodeMaintaining Source Code

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VVVVVVVVVVVV

Colorado River

North Rim of theGrand Canyon

South Rim of theGrand Canyon

Classic Software Development Challenge #1:Multiple Models

DataModels

FunctionModels

User InteractionUser Interaction(Behavior)(Behavior)

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VVVVVVVVVVVV

Colorado River

North Rim of theGrand Canyon

South Rim of theGrand Canyon

Classic Software Development Challenge #2:Model Transformation

DesignModels

AnalysisModels

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Classic Software Development Challenge #3:Maintaining Source Code

Begin “Caller” Program Init x,y,z... Open (files/database) Read... Compute...

DO “Callee” with x,y,z

Update (files/database) Close (files/database) End Main Program

Procedure Callee Parameters x,y,z Compute... End Procedure

End Program

Spaghetti?

Who wrotethis code?

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SOLUTION

Colorado River

ObjectTechnology

INTEGRATED MODEL(S)(function, data, behavior)

(analysis, design and implementation)

ROUND-TRIPENGINEERING

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A SimplifiedObject-Oriented

Systems AnalysisMethodology

O-O Systems Analysis Methodology

1. Identify the information system’s purpose

2. Identify the information system’s 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 Simplified Object-Oriented Systems Analysis Methodology

Activities

Software Development’s “Separation of Concerns”

Problem Domain

Data Management System Interaction

Information System

Human Interaction

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The Unified Modeling Language (UML)

Models and Notation

O-O Systems Analysis O-O Systems Analysis MethodologyMethodology

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Subject Matter Expert & Notation

Can you draw a stick figure of a person?

Can you draw a picture of an automobile?

Can you draw a picture of the space shuttle?

Can you draw a picture of an Oopsla?

Why not?

Subject Matter Expert (SME)

Notation - symbols used to communicate

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Booch Jacobson Rumbaugh

“The 3 Amigos”

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Information Systems Development

People Process

Technology(UML - notation & tools to use it)

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The Object Management Group (OMG), formed in

1989, is a consortium of about 800 software

vendors, consultants and end user organizations

whose mission is to develop STANDARD interfaces

for INTEROPERABLE software components in

HETEROGENEOUS computing environments.

Version 1.1 of the UML was adopted as an OMG Standard on November 14, 1997

www.omg.org

The OMG Revision Task Force released UML Version 1.3 in the Fall of 1998

The 9 Diagrams of the UML ClassClass ObjectObject Use-CaseUse-Case Interaction/Scenario Diagrams:Interaction/Scenario Diagrams:

– SequenceSequence

– CollaborationCollaboration

State [-Transition]State [-Transition] ActivityActivity ComponentComponent DeploymentDeployment

Implementation(Static)

Behavior

Static

A Package is used for Model Management

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UML

Diagrams

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“The Big Picture”

A Video Store UML

Class Diagram

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End of

“The Big Picture”

QUITTING TIME

97 CONCEPTUAL DESIGN: AN OVERVIEW OF METHODOLOGIES, MODELS AND NOTATIONS.

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Transcript of 97 CONCEPTUAL DESIGN: AN OVERVIEW OF METHODOLOGIES, MODELS AND NOTATIONS.