Introduction information systems

Systems Analysis & Design!Sixth Edition!

SYSTEM DESIGN TOPICS

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Objectives

●  Identify various types of information systems and explain who uses them

●  Explain systems development tools, including modeling, prototyping, and CASE tools

●  Distinguish between structured analysis and object-oriented methodology

●  Describe the systems development life cycle ●  Discuss the role of the information

technology department and the systems analysts who work there

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Information System Components

●  A system is a set of related components that produces specific results

●  A mission-critical system is one that is vital to a company’s operations

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●  Hardware ●  Software

–  System software –  Network operating system –  Application software –  Enterprise applications –  Horizontal system –  Vertical system


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●  Data –  Is the raw material that an information system

transforms into useful information –  Tables –  Linking

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●  Processes –  Define the tasks and business functions that users,

managers, and IT staff members perform to achieve specific results

●  People –  Users, or end users, are the people who interact with

an information system, both inside and outside the company

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Impact of the Internet

●  E-Commerce (I-Commerce) ●  B2C (Business-to-Consumer) ●  B2B (Business-to-Business)

–  EDI, XML, HTML ●  Web-Based Development

–  WebSphere, .NET –  Web services

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How Business Uses Information Systems

●  In past, IT managers divided systems into categories based on the user group the system served –  Office systems –  Operational systems –  Decision support systems –  Executive information systems

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●  Today, it makes more sense to identify a system by its functions, rather than by users –  Enterprise computing systems –  Transaction processing systems –  Business support systems –  Knowledge management systems –  User productivity systems

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●  Enterprise computing systems –  Support company-wide operations and data

management requirements –  Enterprise resource planning (ERP)

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●  Transaction processing systems –  Efficient because they

process a set of transaction-related commands as a group rather than individually

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●  Business support systems –  Provide job-related

information to users at all levels of a company

–  Management information systems (MIS)

–  What-if

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●  Knowledge management systems –  Called expert systems –  Simulate human reasoning by combining a

knowledge base and inference rules –  Many use fuzzy logic

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●  User productivity systems –  Technology that improves productivity –  Groupware

●  Information systems integration –  Most large companies require systems that combine

transaction processing, business support, knowledge management, and user productivity features

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Information System Users and Their Needs

●  A systems analyst must understand the company’s organizational model in order to recognize who is responsible for specific processes and decisions and to be aware of what information is required by whom

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Information System Users and Their Needs

●  Top managers ●  Middle Managers and Knowledge Workers ●  Supervisors and Team Leaders ●  Operational Employees ●  Strategic plans

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Systems Development Tools and Techniques

●  Systems analysts must know how to use a variety of techniques such as modeling, prototyping, and computer-aided systems engineering tools to plan, design, and implement information systems

●  Systems analysts work with these tools in a team environment

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●  Modeling –  Used to describe and simplify an information system: –  Business model –  Requirements model –  Data model –  Object model –  Network model –  Process model

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●  Prototyping –  Prototype –  Speeds up the development process significantly –  Important decisions might be made too early –  Can be an extremely valuable tool

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●  Computer-Aided Systems Engineering (CASE) Tools –  Framework for systems development and support a

wide variety of design methodologies –  CASE tools

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Systems Development Methods

●  Structured analysis and object-oriented analysis are both popular methodologies for developing computer-based information systems

●  A systems analyst should understand the alternative methodologies and their individual strengths and weaknesses

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●  Structured Analysis –  Uses a set of process models to describe a system

graphically –  Systems development life cycle (SDLC)

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●  Object-oriented (O-O) analysis –  O-O analysis combines data & processes into objects –  Object is a member of a class –  Class is a collection of similar objects –  Objects possess properties –  Methods change an object’s properties –  Messages request specific behavior or information

from another object

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●  Joint Application Development and Rapid Application Development –  JAD – Team based fact finding –  RAD – compressed version of the entire process

●  Other development methodologies –  Microsoft Solutions Framework (MSF)

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The Systems Development Life Cycle

●  SDLC used to plan and manage the systems development process

●  It includes the following steps: –  Systems planning phase –  Systems analysis phase –  Systems design phase –  Systems implementation phase –  Systems operation, support, and security phase

–  Deliverable or end product

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●  Traditionally pictured as a waterfall model, but is also presented as an interactive model depicting real world practice and the constant dialog among users, managers, and systems developers

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●  Systems planning (preliminary investigation ) –  Purpose is to identify the nature and scope of the

business opportunity or problem –  Systems request – begins the process & describes

problems or desired changes –  Systems planning includes preliminary investigation

whose key part is a feasibility study

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●  Systems Analysis –  Purpose is to build a logical model of the new system –  First step is requirements modeling, where you

investigate business processes and document what the new system must do

–  Second step is data and process modeling –  Third step is object modeling –  Fourth step is transition to system design –  End product is the system requirements document

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●  Systems Design –  Purpose is to create a blueprint that will satisfy all

documented requirements –  Identify all outputs, inputs, and processes –  Avoid misunderstanding through manager and user

involvement –  End product is systems design specification

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●  Systems Implementation –  New system is constructed –  Write, test, & document programs –  File conversion occurs –  Users, managers, IT staff trained to operate and

support the system –  Systems evaluation performed

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●  Systems operation, support, and security –  New system supports operations –  Maintenance changes correct errors or meet

requirements –  Enhancements increase system capability –  Well-designed system will be secure, reliable,

maintainable, and scalable

–  SDLC ends with system replacement

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Systems Development Guidelines

–  Planning –  Involve users throughout the development process –  Listening is very important –  Create a time table with major milestones –  Identify interim checkpoints –  Remain flexible –  Develop accurate cost and benefit information

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Information Technology Department

●  The information technology (IT) department develops and maintains a company’s information systems

●  The IT group provides technical support

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●  Application Development –  Team may include users, managers and IT staff

members ●  Systems Support and Security

–  Provides hardware and software support ●  User Support

–  Provides users with technical information, training, and productivity support

–  Help desk

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●  Database Administration –  Database design, management, security, backup, and

user access ●  Network Administration

–  Includes hardware and software maintenance, support, and security

●  Web Support –  Design and construction of Web pages and presence –  Important for e-commerce

–  Webmaster

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The Systems Analyst Position

●  A systems analyst investigates, analyzes, designs, develops, installs, evaluates, and maintains a company’s information systems

●  On large projects, the analyst works as a member of an IT department team

●  Smaller companies often use consultants to perform the work

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Summary

●  IT is a combination of hardware and software that support business

●  The essential components of an information system are hardware, software, data, processes, and people

●  Companies are product-oriented, service-oriented, or a combination of the two

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Summary

●  Organization structure usually includes levels. Each level has different responsibilities and information needs

●  Systems analysts use modeling, prototyping, and CASE tools. Modeling produces a graphical representation of the process, prototyping involves creation of an early working model, and CASE tools assist in various systems development tasks

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Summary

●  The Systems Development Life Cycle (SDLC) consists of five phases: systems planning, systems analysis, systems design, systems implementation, and systems operation, support, and security

●  Systems analysts need a combination of technical and business knowledge, analytical ability, and communication skills

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TOPICS

3- USER INTERFACE, INPUT AND OUTPUT DESIGN

4. DATA DESIGN

5. APPLICATION ARCHITECTURE

6. APPLICATION DEVELOPMENT

SYSTEM IMPLEMENTATION

7. INSTALLATION AND EVALUTION

SYSTEM OPERATION AND SUPPORT

1- OBJECT MODELING

2- TRANSITION TO SYSTEMS DESIGN

SYSTEM DESIGN

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PHASE 2 SYSTEMS ANALYSIS

●  CHAPTER 5 OBJECT MODELING

1- OBJECT-ORIENTED TERMS AND CONCEPTS 2- RELATIONSHIPS AMONG OBJECTS AND CLASSES 3- OBJECT MODELING WITH THE UNIFIED MODELING LAGUAGE (UML)

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PHASE 2 SYSTEMS ANALYSIS

●  CHAPTER 6 TRANSITION TO SYSTEMS DESIGN 1- EVALUATING SOFTWARE ALTERNATIVES 2- STEPS IN EVALUATING AND PURCHASING SW PACKAGES 3- COMPLETION OF SYSTEMS ANALYSIS 4- TRANSITION TO SYSTEM DESIGN 5- PROTOTYPING 6- DESIGNING AND USING CODES

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PHASE 3 SYSTEMS DESIGN

●  CHAPTER 7 USER INTERFACE, INPUT DESIGN AND OUTPUT DESIGN

1- USER INTERFACE DESIGN 2- INPUT DESIGN 3- OUTPUT DESIGN ISSUES 4- PRINTED OUTPUT

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•  CHAPTER 8 DATA DESIGN

●  1- DATA DESIGN CONCEPTS ●  2- DATA DESIGN TERMINOLOGY ●  3- DATA RELATIONSHIPS (E-R) ●  4- NORMALIZATION ●  5- STEPS IN DATABASE DESIGN

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•  CHAPTER 9 APPLICATION ARCHITECTURE

1- CLIENT/SERVER ARCHITECTURE 2- PROCESSING METHODS (ON-LINE, BATCH AND

COMBINATION) 3- NETWORK MODELS 4- SYSTEM MANAGEMENT AND SUPPORT

( PERFORMANCE, SECURITY, BACKUP, FAULT,..)

5- SYSTEM DESIGN COMPLETION

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PHASE 4 SYSTEMS IMPLEMENTATION ●  CHAPTER 10

APPLICATION DEVELOPMENT 1- QUALITY ASSURANCE 2- STRUCTURED APPLICATION DEVELOPMENT

(STRUCTURE CHARTS) 3- CODING 4- OBJECT-ORIENTED APPLICATION DEV. 5- TESTING THE APPLICATION (UNIT,

INTEGRATION AND SYSTEM)

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PHASE 4 SYSTEMS IMPLEMENTATION ●  CHAPTER 11

INSTALATION AND EVALUATION

●  1- OPERATIONAL AND TEST ENVIROMENTAL ●  2- TRAINING ●  3- SYTEM CHANGOVER ●  4- DATA CONVERSION ●  5- FINAL REPORT TO MANAGEMENT

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PHASE 5 SYSTEMS OPERATION AND SUPPORT

●  CHAPTER 12 – SYSTEMS OPERATION AND

SUPPORT

●  1- USER SUPPORT ACTIVITIES

●  2- MAINTENANCE ACTIVITIES (CORRECTIVE, ADAPTIVE, PERFECTIVE AND PREVENTIVE)

●  3-MANAGING SYSTEM PERFOMANCE ●  4- SYSTEM OBSOLESCENCE

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●  THANKS FOR ALL

Introduction information systems

Technology

Transcript of Introduction information systems