Chapter 12Chapter 12Systems DevelopmentSystems Development

The StrategicManagement of

InformationTechnology

Transaction Processing Transaction Processing SystemSystem

Input OutputProcess

Information

Communication

Systems Development

Systems Development Life Cycle Consists Of Six Phases

Systems Planning Systems Analysis General Systems Design Systems Evaluation and Selection Detailed Systems Design Systems Implementation

3 Categories of Systems 3 Categories of Systems DesignDesign

Global-Based Systems Group-Based Systems Local-Based Systems

Global-Based SystemsGlobal-Based Systems Large, Complex Information Systems that Process High Transaction

Volumes Complete Overhaul or Replacement of Systems Design Components

– Old output is changed from monthly tabular reports to online screen displays

– New processes are developed– Input captured by scanning devices– Old hierarchical database is converted to new relational database

with standard query language– Controls are installed– New technology platform composed of enterprise-wide network

topology supports systems design components

Group-Based SystemsGroup-Based Systems

Serve a Single Department or other specific group of users

– smaller than, connected to global-based system

Local-Based SystemsLocal-Based Systems

Concentration on Local Environment

Rapid Application DevelopmentRapid Application Development

Joint Application Development (JAD) Specialists with Advanced Tools (SWAT) Computer-Aided Systems and Software

Engineering (CASE Tools) Prototyping

Design ApproachesDesign Approaches

Process-Oriented Approach Data-Oriented Approach Object-Oriented Approach

Design PrinciplesDesign Principles Modularity

– Maintainability– Reusability

Libraries of object class catalogs– Reliability– Extendibility– Standardized– Independence– Variety in Use– Top-Down Design

Start with Abstract Description of New System Refine View in Successive Steps

– Bottom-Up Design Start with Objects and Assemble them to completed product

Process-Oriented ApproachProcess-Oriented Approach

Based upon Stable Set of Input, Process, and Output

Transactions-Based Applications– Accounts Payable– Accounts Receivable– Payroll– Inventory Control

Data-Oriented ApproachData-Oriented Approach

Undefined Systems Processes Define All Needed Data Attributes Systems Analysts must determine, with

users, how the system will be used

Data-Oriented Approach: Data-Oriented Approach: StepsSteps

Discuss potential decisions that will be made from system with users of system– Model the purchasing decision support system

through use of flexible modeling tool Product Quality Past Performance Product Availability

– Divide Each Criterion into Attributes– Develop Data Dictionary

Size, Type, Description, Limits and Exceptions, Ranges, Security Level, Access Privileges

Changes, Description, Order

Object-Oriented ApproachObject-Oriented Approach Catalog objects

– Found by keywords– In a Library or Database

Objects– Exhibit certain behaviors– Attributes and operations are encapsulated or

pulled together– Operations describes how attributes are

processed– Behave in certain ways in response to messages

Object-Oriented ApproachObject-Oriented Approach

Classes

– Set of Objects that share common structure and behavior

Inheritance

– Objects receive attributes and operations from other objects

– Add more attributes and operations of their own Polymorphism

– Ability of object to respond to and implement each object

Object-Oriented StepsObject-Oriented Steps

Identify Object Class Identify Relationships Identify Attributes Determine Inheritance Relationships Build Class Hierarchy

– Order– Transaction Process– Tools Inventory

Joint Application DevelopmentJoint Application Development

Conceptual Systems Design Model– Data Flow Diagram– Entity Relationship Diagram– Decision Table– Screen Prototype– Decision Tree

SDLC StrengthsSDLC Strengths

Provide Control over Development Process Formality

SDLC WeaknessesSDLC Weaknesses

Increased Cost of Development Lengthened Development Time Difficult when Project is Hard to Define

End-User DevelopmentEnd-User Development

Users Develop the Prototypes Fourth-Generation Languages CASE Tools

Steps Toward IntegrationSteps Toward Integration

Windowing Operating System– OS/2 Presentation Manager

– Windows

– X-Windows (Sun) Transaction Processing Systems

– Payroll Services

– Sales Order Processing Systems

– Process Control Systems

– Corporate Accounting Systems

Steps Toward IntegrationSteps Toward Integration

Multi-Tasking– Allow Users to run different programs at the same

time– Windows– OS/2 (Presentation Manager)– XWindows

Networks– Enable Dynamic Integration from Several Sources

IntegrationIntegration

Vertical– Different Levels of Production– ex: Oil Company

Horizontal– Retail Stores– ex:Wal-Mart

Object-OrientationObject-Orientation Different than Transmitting Raw Bits of Data

– Hardware Connections– Access Controls– Simple Data Formats

Software Agents– object-oriented programs written to perform specific tasks in

response to user requests– agents know how to exchange object attributes– agents have the ability to activate object functions in other

agents Multimedia

– Integration of Text, Video, Sound, Pictures, Animation

Integration/LinksIntegration/Links Static

– Hard-Coded

– Import Dynamic

– Linked

– Dynamic Data Exchange (DDE)

– Hot-Linked

– Object-Linking and Embedding (OLE) Original Software Package Automatically started

when chosen

Systems Project ProposalsSystems Project Proposals Feasibility Factors

– Technical

– Economic

– Legal

– Operational

– Schedule Strategic Factors

– Productivity

– Differentiation

– Management

Systems PlanSystems Plan

Business Plan– Document Company’s Goals and Objectives– Align Systems Project with Company’s Business

Plan Enterprise-Wide Model

– Entity Relationship Diagram showing relationship between organization’s entities and their relationship to supporting strategies of Business Plan

– View of Future Organization of Enterprise under a Business Plan

Two Levels of PlanningTwo Levels of Planning

Systems Planning– Gives Managers, Users, and Information

Systems Personnel Projects– Establishes what should be done– Sets a budget for the total cost of these projects

Systems Project Planning– Setting a plan for the development of each

specific systems project

Systems Professional SkillsSystems Professional Skills Systems Planning

– Form project team after proposed systems project is cleared for development

Systems Analysis– Business Systems Analysts knowledgeable in business

General Systems Design– Business Systems Analysts

Systems Evaluation and Selection– Business Systems Analysts

Detailed Systems Design– Wide Range of Systems and Technical Designers

Systems Implementation– Systems analysts, programmers, and special technicians

Effective Leadership StyleEffective Leadership Style Autocratic Style

– Crisis-Style Management– Used to Correct Major Problem, such as Schedule

Slippage Democratic Style

– Team-oriented Leadership– Gives each team member the freedom to achieve goals

which he/she helped set Laissez-Faire Style

– Highly-motivated, Highly-Skilled Team Members– People who work best alone

Project Management SkillsProject Management Skills Planning

– States what should be done– Estimates how long it will take– Estimates what it will cost

Leading– Adapts to dynamics of enterprise and deals with setbacks– Guides and induces people to perform at maximum abilities

Controlling– Monitors Progress Reports and Documented Deliverables– Compares Plans with Actuals

Organizing– Staffs a Systems Project Team– Brings together users, managers, and team members

CASECASE Computer-Aided Systems and Software Engineering Increase Productivity of Systems Professionals Improve the Quality of Systems Produced Improve Software Maintenance Issue Includes:

– workstations– central repository– numerous modeling tools– project management– Systems Development Life Cycle Support– Prototyping Applications– Software Design Features

Central RepositoryCentral Repository

Models Derived from Modeling Tools Project Management Elements Documented Deliverables Screen Prototypes and Report Designs Software Code from Automatic Code Generator Module and Object Libraries of Reusable Code Reverse Engineering, Reengineering, and

Restructuring Features

Software MaintenanceSoftware Maintenance Reverse Engineering

– Extract original design from spaghetti-like, undocumented code to make maintenance change request

– Abstract meaningful design specifications that can be used by maintenance programmers to perform maintenance tasks

Reengineering– Examination and changing of a system to reconstitute it in

form and functionality– Reimplementation

Restructuring– Restructures code into standard control constructs

sequence, selection, repetition

Work Group TechnologiesWork Group Technologies

Suite of Products GroupWare

Examples of Suite of ProductsExamples of Suite of Products

Microsoft Corporation

– Word

– Excel

– PowerPoint Lotus Development Corporation

– AmiPro

– Lotus 1-2-3

– Freelance Novell/Borland

– WordPerfect

– Borland

– dBaseIV

Advantages of Suite of ProductsAdvantages of Suite of Products

Integrated Document Economies of Scale Consolidated Training Shared Files Across Group

Disadvantages of Suite of ProductsDisadvantages of Suite of Products

Choice Based upon Group Rather than Advantages of Individual Product

“Locked In” to Product Company Difficulty in Matching Client Requirements

Today’s OrganizationToday’s Organization

Enterprise-Wide Development Object-Oriented Definition Implementation of Suite Approach

Unsuccessful SystemsUnsuccessful Systems

Systems were developed which did not support business strategies and objectives.

Poor systems planning and inadequate project management. Failure to define or understand user requirements. Negligence in estimating costs and benefits of the systems project. Creation of a myriad of design defects and errors. Acquisition of computers and software that no one needs or knows how

to use. Installation of incompatible or inadequate technology. Negligence in implementing adequate controls. Development of unstructured, unmaintainable software. Inadequate implementation tasks.

PDMPDM

ProductivityDifferentiationManagement

Project ManagementProject Management

Gantt Chart Pert Chart

Gantt ChartGantt Chart

Compares Planned Performance against actual performance to determine whether the project is ahead of, behind, or on schedule

Schedule a complete systems project by phases

PERT ChartPERT Chart Estimate, Schedule, and Control a network of interdependent tasks Shown by arrows, nodes, or circles Program, Evaluation and Renew Technique Determine minimum time needed to complete a project, phase, or task Critical Path

– Minimum time needed to complete a project or phase– Total of the most time-consuming chain of events

Four Steps– Identify Tasks– Determine Proper Sequence of Tasks– Estimate the Time Required to Perform each Task– Prepare Time-Scaled Chart of Tasks and Events to Determine the

Critical Path