8.2 system analysis and design

1 - 1

Systems Analysis Systems Analysis and Designand Design

1 - 2

Key Ideas Many failed systems were abandoned

because analysts tried to build wonderful systems without understanding the organization.

The primarily goal is to create value for the organization.

1 - 3

Key Ideas The systems analyst is a key person analyzing

the business, identifying opportunities for improvement, and designing information systems to implement these ideas.

It is important to understand and develop through practice the skills needed to successfully design and implement new information systems.

1 - 4

THE SYSTEMS THE SYSTEMS DEVELOPMENT LIFE DEVELOPMENT LIFE CYCLECYCLE

1 - 5

Major Attributes of the Life Cycle

The project --Moves systematically through phases where

each phase has a standard set of outputsProduces project deliverablesUses deliverables in implementationResults in actual information systemUses gradual refinement

1 - 6

Project Phases

Planning (Why build the system? How should the team go about building it?)

Analysis (Who uses system, what will it do, where and when will the system be used?)

Design (How will the system work?) Implementation (System delivery)

1 - 7

A simple process for making lunch

1 - 8

Identifying business value Analyze feasibility Develop work plan Staff the project Control and direct project

Planning

1 - 9

Analysis strategy Gathering business requirements Requirements definition use cases Process modeling Data modeling

Analysis

1 - 10

Design selection Architecture design Interface design Data storage design Program design

Design

1 - 11

ConstructionProgram buildingProgram and system testing

InstallationConversion strategyTraining planSupport plan

Implementation

1 - 12

Processes and Deliverables

Process Product

Planning

Analysis

Design

Implementation

System RequestFeasibility Analysis

Workplan

System Proposal

System Specification

New System and Maintenance Plan

Why systems fail?

Did not support business strategies Poor planning and project management Failure to understand user requirements Poor cost estimating and benefit analysis Design defects Incompatible or inadequate technology Lack of adequate controls Unstructured, unmaintainable software

What makes successful systems?

User involvement Systems planning and project management Developing alternative designs Functional design guides detailed design Complete, concise, and clear documentation Using a coordinated, planned approach Post implementation reviews Designing for systems maintenance

1 - 15

SDLC MODELSSDLC MODELS

Waterfall model: has well-defined, linear stages of systems development and support.

Spiral model: shows that software is developed using an iterative or spiral approach rather than a linear approach.

Prototyping model: used for developing prototypes to clarify user requirements.

1 - 16

Waterfall Model

1 - 17

Pros and Cons of the Waterfall Model

Pros Cons

Identifies systems requirements long before programming begins

Minimizes changes to requirements asproject progresses

Design must be specified on paper before programming begins

Long time between system proposal and delivery of new system

1 - 18

Prototype Model

1 - 19

Pros and Cons of Prototype Model

Pros Cons

Reduces Schedule Time

Less Chance ofRework

Still Uses PaperDocuments

Sub-projects May BeDifficult to Integrate

1 - 20

Spiral Model

1 - 21

Pros and Cons of Spiral Model

Pros Cons

High amount of risk analysis

Software is produced early in the software life

cycle

Can be a costly model to use

Doesn’t work well for smaller projects

1 - 22

Criteria for Selecting the Appropriate Methodology

Clear user requirements Familiarity with technology Complexity of system Reliability of system Time schedule Schedule visibility

1 - 23

TEAM ROLES AND SKILLSTEAM ROLES AND SKILLS

1 - 24

Information Systems Roles

Business Analyst Database Administrator Systems analyst Technical Lead/Architect Application Developers Software Quality Assurance Analyst Technical Support

1 - 25

Summary The Systems Development Lifecycle consists of four

stages: Planning, Analysis, Design, and Implementation

There are six major development methodologies: the waterfall method, the parallel development method, the phased development method, system prototyping, design prototyping, and agile development.

There are five major team roles: business analyst, systems analyst, infrastructure analyst, change management analyst and project manager.

1 - 26

The End