Transition from Systems Analysis to Systems Design

What is Systems Analysis?

• is a problem-solving method that involves looking at the wider system, breaking apart the parts and figuring out how it works in order to achieve a particular goal.

Systems analysis involves looking at inputs, outputs, mechanisms and controls

Systems Analysis

The first step in solving a problem that involves a system is analyzing that system. This involves breaking it down into the parts that make it up, and seeing how those parts work together. Sometimes figuring out how a system works can involve turning off parts of the system and seeing what happens, or changing parts of the system and seeing what the result is.

Systems Analysis

Structured Analysis•“Structured analysis is a set of techniques and graphical tools that allow the analyst to develop a new kind of system specification that are easily understandable to the user. Analysts work primarily with their wits, pencil and paper.” [Kendall 1996]•Uses a set of process models to describe a system graphically•The availability of CASE tools in the 1990s enabled analysts to develop and modify the graphical SASD models.

Systems Analysis

• Object-oriented (O-O) analysis– O-O analysis combines data & processes into

things called objects– O-O analysis uses object models to represent

data and behavior, and to show how objects affect other objects

– By describing the objects (data) and methods (processes) needed to support business operation, a system developer can design reusable components that allow faster system implementation and decreased development cost

Systems Analysis

Object-oriented (O-O) analysis• objects combine data and processes. Object are the end

product of object-oriented analysis. Object is a member of a class

• Class is a collection of similar objects• Objects possess characteristics called properties• Properties inherits from the object class or possesses on

its own• In O-O design, built-in processes called methods can

change an object’s properties• Object can send information to another object by using a

message• A message requests specific behavior or information from

another object

Object-oriented (O-O) Object-oriented (O-O) analysisanalysis

The PERSON class includes INSTRUCTOR and STUDENT objects, which have their own properties and inherited properties.

• Joint Application Development and Rapid Application Development– JAD – The basic idea behind JAD is to bring

structure to the requirements determination phase of analysis and to the reviews that occur as a part of design.

– Team based fact finding– Users, Managers and Analysts work together for

several days

– System requirements are reviewed

– Structured meetings

.

– RAD – created to radically decrease the time needed to design and implement information systems.

– RAD relies on extensive user involvement.

• Incorporate special techniques and tools:– CASE tools

– JAD sessions

– Fourth generation/visualization programming languages

– Code generators

.

What is System Designs?

• is the process of defining the elements of a system such as the architecture, modules and components, the different interfaces of those components and the data that goes through that system

• it is meant to satisfy specific needs and requirements of a business or organization through the engineering of a coherent and well-running system.

What is the most important thing to be aware of in systems design?

A systems approach to design asks:

•For this situation, what is the system?•What is the environment?•What goal does the system have in relation to its environment?•What is the feedback loop by which the system corrects its actions?

What is the most important thing to be aware of in systems design?

• How does the system measure whether it has achieved its goal?

• Who defines the system, environment, goal, etc.—and monitors it?

• What resources does the system have for maintaining the relationship it desires?

• Are its resources sufficient to meet its purpose?

The Transition to Systems Design

• Preparing for Systems Design Tasks– It is essential to have an accurate and

understandable system requirements document

• Logical and Physical Design– The logical design defines the functions

and features of the system and the relationships among its components

– The physical design of an information system is a plan for the actual implementation of the system