CS301 X Information Systems: Analysis & Design: The Systems Development Environment

Systems Development Life Cycle (SDLC) (Cont.) #2

Design - a description of the recommended solution is converted into logical and then physical system specifications. Logical design - all functional features of the system chosen for development in analysis are described independently of any computer platform.

Computer-Aided Software Engineering (CASE) Tools

Diagramming tools enable graphical representation. Computer displays and report generators help prototype how systems "look and feel".

Systems Development Life Cycle (SDLC) (Cont.) #4

Implementation - the information system is coded, tested, installed and supported in the organization. Maintenance - an information system is systematically repaired and improved.

A Modern Approach to Systems Analysis and Design

1950s: focus on efficient automation of existing processes. 1960s: advent of 3GL, faster and more reliable computers. 1970s: system development becomes more like an engineering discipline

The Heart of the Systems Development Process

Analysis -> Design -> Code -> Test. (In a circle). Planning -> Analysis -> Design -> Implementation -> Maintenance. (In a circle, back & forth between Analysis & Design before going to Implementation)

Information Systems Analysis & Design

Complex organizational process. Used to develop and maintain computer-based information systems. Used by a team of business and systems professionals.

Systems Development Life Cycle (SDLC) (Cont.) #3

Physical design - the logical specifications of the system from logical design are transformed into the technology-specific details from which all programming and system construction can be accomplished.

Systems Development Life Cycle (SDLC) (Cont.)

Planning - an organization's total information system needs are identified, analyzed, prioritized, and arranged. Analysis - system requirements are studied and structured.

Developing Information Systems

System Development Methodology is a standard process followed in an organization to conduct all the steps necessary to analyze, design, implement, and maintain information systems.

Problems with Waterfall Approach

System requirements "locked in" after being determined (can't change). Limited user involvement (only in requirements phase). Too much focus on milestone deadlines of SDLC phases to the detriment of sound development practices.

Systems Development Life Cycle (SDLC)

Traditional methodology used to develop, maintain, and replace information systems. Phases in SDLC: Planning, Analysis, Design, Implementation, Maintenance

Computer-Aided Software Engineering (CASE) Tools (Cont.)

Analysis tools automatically check for consistency in diagrams, forms, and reports. A central repository provides integrated storage of diagrams, reports, and project management specifications.

Computer-Aided Software Engineering (CASE) Tools (Cont.) #2

Documentation generators standardize technical and user documentation. Code generators enable automatic generation of programs and database code directly from design documents, diagrams, forms, and reports.

Rapid Application Development (RAD)

Methodology to radically decrease design and implementation time. Involves: extensive user involvement, prototyping, JAD sessions, integrated CASE tools, and code generators.

Standard and Evolutionary Views of SDLC

Planning -> Analysis -> Design -> Implementation -> Maintenance -> Planning.

Traditional Waterfall SDLC

Planning -> Analysis -> Logical Design -> Physical Design -> Implementation -> Maintenance.

A Modern Approach to Systems Analysis and Design (Cont.)

1980s: major breakthrough with 4GL, CASE tools, object oriented methods. 1990s: focus on system integration, GUI applications, client/server platforms, Internet The new century: Web application development, wireless PDAs, component-based applications.

A Modern Approach to Systems Analysis and Design (Cont.) #2

Application Software - Computer software designed to support organizational functions or processes. Systems Analyst -Organizational role most responsible for analysis and design of information systems.

Different Approaches to Improving Development

CASE Tools, Rapid Application Development (RAD), Agile Methodologies, eXtreme Programming.

Rapid Application Development (RAD) (Cont.)

Requirements Planning -> User Design -> Construction -> Cutover. (Goes back & forth between Construction & User Design.)