OBJECT ORIENTED SYSTEM ANALYSIS AND DESIGN

COURSE OUTLINE

• The world of the Information Systems Analyst• Approaches to System Development• The Analyst as a Project Manager• Beginning the Analysis: Investigating System

Requirements• Modeling System Requirements

• The Object-Oriented Approach to Requirements

• Evaluating Alternatives for Requirements, Environment, and Implementation

• Moving to Design• The Object-Oriented Approach to Design: Use

Case Realization

• Designing Databases• Designing the User Interface• Designing System Interfaces, Controls and

Security• Making the System Operational• Current Trends in System Development

• System Analysis is really more about understanding a business and its goals and strategies, defining requirements for information systems that support those goals and strategies, and supporting the business.

• The key to successful system development is thorough systems analysis and design to understand what the business requires from the information system.

Definitions

• System Analysis is the process of understanding and specifying in detail what the information system should accomplish.

• Systems design is the process of specifying in detail how the many components of the information system should be physically implemented

• System Analyst is a business professional who uses analysis and design techniques to solve business problems using information technology.

The analyst as a business problem solver

• Developing information systems is not about writing programs but about solving organizational problems. A system analyst is a problem solver rather than a programmer.

INFORMATION SYSTEMS

• A System is a collection of interrelated components that function together to achieve some outcome.

• An information system is a collection of interrelated components that collect, process, store, and provide as output the information needed to complete a business task.

• A subsystem is a system that is part of a larger system

• A supersystem is a larger system that contains other systems

• Functional decomposition is dividing a system into components based on subsystems that, in turn, are further divided into subsystems.

• Functional decomposition involves dividing a system into components

• Components of an information system include hardware, software, inputs, outputs, data, people and procedures.

• System boundary is the separation between a system and its environment that inputs and outputs must cross.

• A system analyst should define the inputs and the outputs

• Automation boundary is the separation between an automated part of a system and the manual part of the system.

• The automated part is where work is done by computers and the manual part is where work is done by people.

TYPES OF INFORMATION SYSTEM

• Transaction processing systems: capture and record information about the transactions that affect the organization. Usually these transactions create credit or debit entries in accounting ledgers. TPSs are often called online transaction processing systems

Management information systems

• Systems that take information captured by transaction processing systems and produce reports that management needs for planning and controlling the business. MISs used by executives often include external data on the competitive environment-news about competitors, stock market reports, economic forecasts, and information from strategic plans

Decision support and knowledge based systems

• They allow a user to explore the impact of available options or decisions or to automate routine decision making.

• Sometimes this process is referred to as “what if” analysis.

• Some of these systems use expertise captured as a knowledge base to mimic the way decisions are made by experts.

• Enterprise applications are highly integrated systems that support company-wide operations and data, often combining aspects of TPSs, MISs, and DSSs/KBSs.

• Communication support systems support systems that allow employees to communicate with each other and with customers and suppliers.

• Office support systems support systems that help employees create and share documents, including reports, proposals, and memos.

Required skills of the systems analyst

• There are three types of knowledge and skills required by systems analyst– Technical – Business– People

Technical knowledge and skills

• The system analyst should understand– Computers and how they work– Devices that interact with computers, including

input, storage and output devices– Communications networks and protocols that

connect computers– Database and database management systems– Programming languages– Operating systems and utilities

• A system analyst needs to know a lot about tools and techniques for developing systems.

• Tools are software products that are used to develop analysis and design specifications and completed system components. Some tools are– Software Packages such as Microsoft Access etc– Integrated development environments(IDE)– Computer-Aided system engineering (CASE)– Program code generator, testing tools, configuration

management tools, software library management tools, documentation support tools, project management tools etc

• Techniques are strategies for completing specific system development activities.

• Some techniques– Project planning techniques– Cost/benefit analysis techniques– Interviewing techniques– Requirements modeling techniques– Architectural design techniques– Network configuration techniques– Database design techniques

Business knowledge and skills

• What business functions do organizations perform?• How are organizations structured?• How are organizations managed?• What type of work goes on in the organization?• What makes the organization successful• What are the strategies and plans of the

organization• What are the traditions and values of the

organization

People Knowledge and skills

• The analyst should understand how people– Think– Learn– React to change– Communicate– Work (in a variety of jobs and levels)