Modern Systems Analysis and Design Third Edition Jeffrey A. Hoffer Joey F. George Joseph S.

Valacich Chapter 1 The Systems Development Environment

Introduction Information Systems Analysis and Design Complex process whereby computer-based information systems are developed and maintained A method used by companies to create and maintain systems that perform basic business functions Main goal is to improve employee efficiency by applying software solutions to key business tasks A structured approach must be used in order to ensure success Application Software Result of systems analysis and design Designed to support specific organizational functions or processes Software engineering processes have been developed to assist in analysis and design Methodologies Comprehensive, multi-step approaches to systems development A sequence of step-by-step approaches that help develop the information system Techniques Processes that are followed to ensure that work is well thought-out, complete and comprehensible to others on the project team Tools Computer programs to assist in application of techniques to the analysis and design process Systems Analyst performs analysis and design based upon: Understanding of organizations objectives, structure and processes

Types of problems managers face and the kind of information needed to solve these problems Knowledge of how to exploit information technology for advantage

Data and Processes Three key components of an information system Data Data Flows Processing Logic Data vs. Information Data Raw facts

Information understand. Data Understanding the source and use of data is key to good system design Various techniques are used to describe data and the relationship amongst data Data Flows Groups of data that move and flow through the system Include description of sources and destination for each data flow Processing Logic Describe steps that transform data and events that trigger the steps Derived from data Organized in a manner that humans can

Approaches to Systems Development Process-Oriented Approach Focus is on flow, use and transformation of data in an information system Involves creating graphical representations such as data flow diagrams and charts Data are tracked from sources, through intermediate steps and to final destinations Natural structure of data is not specified Disadvantage: data files are tied to specific applications Ex: DFD, System Flowchart, UML

Approaches to Systems Development Data-Oriented Approach Depicts ideal organization of data, independent of where and how data are used Data model describes kinds of data and business relationships among the data Business rules depict how organization captures and processes the data Ex: ERD, Relational Schema, Class Diagram

Databases and Application Independence Database Shared collection of logically related data Organized to facilitate capture, storage and retrieval by multiple users Centrally managed

 Designed around subjects Customers Suppliers

Application Independence Separation of data and definition of data from applications

Organizational Responsibilities in Systems Development Systems Analysts work in teams Project Based Includes IS Manager Programmers Users Other specialists

Characteristics of Successful Teams IS Manager May have a direct role in systems development if the project is small Typically involved in allocating resources to and overseeing system development projects. Systems Analyst Diversity of backgrounds Tolerance of diversity Clear and complete communication Trust Mutual Respect Reward structure that promotes shared responsibility

 Key individual in the systems development process Programmers Convert specifications into instructions that the computer understands Write documentation and testing programs Business Managers Have power to fund projects and allocate resources Set general requirements and constraints for projects Other IS Managers/Technicians Database Administrator Involved in design, development and maintenance of databases Network and telecommunications experts Develop systems involving data and/or voice communications Human Factors Specialists Involved in training users and writing documentation Internal Auditors Ensure that required controls are built into the system Skills of a Successful Systems Analyst Analytical Understanding of organizations Problem solving skills System thinking Ability to see organizations and information systems as systems Technical

Understanding of potential and limitations of technology Management Ability to manage projects, resources, risk and change Interpersonal Effective written and oral communication skills

Types of Information Systems and Systems Development Expert Systems (ES) Replicates decision making process Knowledge representation describes the way an expert would approach the problem Ex. XCON-used at Digital Equipment Corp. to design hardware configurations to customer specifications Purpool-financial accounting;evaluates various criteria to make decisions regarding business combinations Cashvalue-assist in capital project planning CFA-cash flow advisor MYCIN-meningitis diagnosis Differences between DSS and ES DSS aim to assists some human decision maker, while ES are designed to replace the decision maker DSS deal mainly with numerical data while ES deal mostly with symbolic data DSS are used to solve ad hoc problems while ES are developed to solve repetitive problems DSS provide neither reasoning nor full explanation capabilities while ES generally include limited reasoning and explanation

Systems Development Life Cycle System Development Methodology Standard process followed in an organization Consists of: Analysis Design Implementation Maintenance

Series of steps used to manage the phases of development for an information system Consists of six phases: Project Identification and Selection Project Initiation and Planning Analysis Design Implementation Maintenance Phases are not necessarily sequential Each phase has a specific outcome and deliverable Individual companies use customized life cycles

Phases of the Systems Development Life Cycle Project Identification and Selection Two Main Activities Identification of need Prioritization and translation of need into a development schedule

 Helps organization to determine whether or not resources should be dedicated to a project. Project Initiation and Planning Two Activities Analysis Study of current procedures and information systems Determine requirements Study current system Structure requirements and eliminate redundancies Design Logical Design Concentrates on business aspects of the system Generate alternative designs Compare alternatives Recommend best alternative Formal preliminary investigation of the problem at hand Presentation of reasons why system should or should not be developed by the organization

Physical Design Technical specifications

Implementation Implementation Hardware and software installation Programming User Training Documentation

Maintenance System changed to reflect changing conditions System obsolescence

Approaches to Development Prototyping Building a scaled-down working version of the system Advantages: Users are involved in design Captures requirements in concrete form

Rapid Application Development (RAD) Utilizes prototyping to delay producing system design until after user requirements are clear Joint Application Design (JAD) Users, Managers and Analysts work together for several days System requirements are reviewed Structured meetings

Improving IS Development Productivity Computer-aided software engineering (CASE) tools Facilitate creation of a central repository for system descriptions and specifications Summary Information systems analysis and design Process of developing and maintaining an information system Modern approach to systems analysis Process-Oriented Data-Oriented

Four types of information systems Transaction Processing (TPS) Management Information Systems (MIS) Decision Support (DSS) Expert Systems (ES) Systems Development Life Cycle (SDLC) Project Identification and Selection Project Initiation and Planning Analysis Design Implementation Maintenance Alternatives to Systems Development Life Cycle Prototyping Rapid Application Development (RAD) Joint Application Design (JAD) Computer-aided software engineering (CASE) tools

References Accounting Information Systems by James A. Hall Chapter 11, pp. 512-527