Copyright Prentice Hall, Inc. 1 Computers: Information Technology in Perspective, 11e Larry Long and Nancy Long Chapter 11 Developing Business Information Systems

Copyright Prentice Hall, Inc.2 Objectives Once you have read and studied this chapter, you will have learned:  The four stages of the system life cycle.  The basic system development techniques and the concepts associated with these techniques.  The scope and capabilities of CASE (Computer-Aided Software Engineering) tools.  The concepts and phases of prototyping, including the general activities that take place during system analysis and design.  Approaches to converting an existing information system to a new one.  Basic programming concepts and the programming process, as well as an overview of popular programming languages.

Copyright Prentice Hall, Inc.3 Why this chapter is important to you! Understanding information systems will help you to be involved in the development process Developing an information system for work can mean the difference between enjoying work or not enjoying work Learning IS concepts will help you to be able to give advice about its effectiveness for upgrades

Copyright Prentice Hall, Inc.4 The System Life Cycle Stages of the Life Cycle  Birth  Development  Production  End-of-life

Copyright Prentice Hall, Inc.5 Applications Software Buy it  Proprietary software package Rent it  Applications service provider (ASP) Make it  Develop a custom information system

Copyright Prentice Hall, Inc.6 System Development Techniques and Concepts Structured System Design  Structure chart encourages top-down designPayrollSystemPayrollSystemEmployeeDatabaseEmployeeDatabaseReportProcessReportProcessGeneralLedgerGeneralLedger CreationCreationMainte-nanceMainte-nanceHourlyHourlySalarySalary

Copyright Prentice Hall, Inc.7 System Development Techniques Entity Symbol Process Flow line Data Storage Data Flow Diagram: Focus is on information flow Entity Relationship Diagram: Focus is on attributes of entities and relationship between them.

Copyright Prentice Hall, Inc.8 System Development Techniques Combination of symbols and flow lines portrays the logic of the program or system Flowcharting Main Program LoopSubroutines Online Storage Input/ Output Display Printed Output Computer Process Predefined Process No Yes Terminal Point Decision

Copyright Prentice Hall, Inc.9 Computer-Aided Software Engineering CASE tools  Design tools  Information repository tools  Program development tools Software engineers Custom programs

Copyright Prentice Hall, Inc.10 Design Tools The CASE design tools  User interface  Screen generator  Layout  Report generator Information repository tools  Cross-referencing system (database)  Packages system documentation Program development tools  Application generator  Generation of text data

Copyright Prentice Hall, Inc.11 Prototyping Developing Prototype Systems  Scalable systems  System specifications (specs)  Functional specifications Three Objectives  Analyze current situation  Identify information needs  Develop a model of the target system Rapid Application Development (RAD)

Copyright Prentice Hall, Inc.12 The Emergence of Prototyping Project teams are able to use CASE tools to create a prototype  Changes can be made along the way  Specs can be added/edited along the way

Copyright Prentice Hall, Inc.13 The Prototyping Process Phase I  Define System Specifications Phase II  Create Prototype System Phase III  Develop Operational System Phrase IV  Develop System Specifications

Copyright Prentice Hall, Inc.14 System Conversion and Implementation Systems and acceptance testing  Unit testing  Systems testing  Uses test data and then live data Approaches to system conversion  Parallel conversion  Direct conversion  Phased conversion  Pilot conversion

Copyright Prentice Hall, Inc.15 The System Becomes Operational Emphasis switches from development to operations  System Maintenance  Modifications  Patches

Copyright Prentice Hall, Inc.16 Programming A program solves a problem  Uses logic  Design program logic before writing it  Nothing more than a set of instructions Programming Languages:  Machine Language  Procedure-Oriented: COBOL  Object-Oriented (OOP): Smalltalk and C++  Fourth Generation (4GL)  Visual Programming: Visual BASIC

Copyright Prentice Hall, Inc.17 Writing the Program System specification review Program identification and description Coding, testing, and documentation

Copyright Prentice Hall, Inc.18 Summary The System Life Cycle System Development Techniques and Concepts Computer-Aided Software Engineering Prototyping System Conversion and Implementation Programming