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System Development Methods

CT046-3-2

Structured System Analysis Design

Method

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CT046-3-2 System Development Methods Structured System Analysis and Design Methods Slide 2 (of 19)

Topic & Structure of the lesson

Structured Systems Analysis and design

(SSADM)

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Learning Outcomes

By the end of this lecture, YOU

should be able to

Design and apply the SSADM systems

methodologies in the development of an

Information System

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Key Terms you must be able to use

If you have mastered this topic, you should be

able to use the following terms correctly in your

assignments and exams:

SSADM

Feasibility study

Requirement analysis

Requirement specification

Logical system

Physical system

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Structured System Analysis Design

Method (SSADM)

Common in UK

Highly structured

Document oriented Five modules with seven stages

Precisely defined task for each stage to ensure

end products

Covers lifecycle from feasibility study to design

Implementation and maintenance is not covered

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Modules in SSADM

Feasibility study

Requirement analysis

Requirement specification

Logical system specification

Physical design

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Stage 0 Feasibility Study

Involves a high level analysis of a business area that the project is feasible, technically possible and the benefits will outweigh the

cost

this phase has four steps

Prepare for the study

Define the problem

Select feasibility option

Create feasibility report

System investigation techniques such as:

Interview, questionnaires and so on

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Requirement Analysis

Current business environment is modeled in terms of

processes

System requirements are identified

This module have two stages

Stage 1 Investigation of current environment

Stage 2 Business system options

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Stage 1 Investigation of Current

SystemMost of the work in repeated in more details, eg the DFD in

feasibility is more detailed. Investigating current

processing needs. Physical model mapped to the logical

DFD.

Establish analysis framework

Investigate and define requirements

Investigate current processing

Investigate current data

Derive logical view of current services

Assemble investigation result

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Stage 2 Business System

Options

At this stage the functionality of new systemis determined.

Define business system options

Select business system options Define requirements

Only cost-justified requirements are the focus

DFD and Entity models are developed but

largely narrative.

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Requirements Specification

Detailed functional and non-functionalrequirements are identified

New techniques are introduced to define the

required processing and data structures

Optional prototyping maybe done, throwaway

type

ELH is constructed, documenting all events

affecting an entity This module has one stage

Stage 3 Definition of requirements

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Stage 3 Definition of

Requirements

Define required system processing

Develop required data model

Derive system functions Enhance required data model

Develop specification prototypes

Develop processing specification Confirm system objectives

Assemble requirements specification

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Logical system specification

Determines Technical System Option which is morelikely to meet the requirements and be cost-effective.

The environment in terms of hardware and software

config and development strategy and system

functionality and constraints eg security, performance

Defining logical design in a non-procedural manner e.g.

dialogues, updates and enquiries elaborating what the

system must do.

This module have 2 stages

Stage 4 Technical system option

Stage 5 Logical design

Both stages are carried out in parallel

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Stage 4 Technical System

Options

Define technical system options

Select technical system options

Define physical design options

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Stage 5 Logical Design

Define user dialogues

Define update processes

Define enquiry process

Assemble logical design

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Physical Design

The logical design is mapped onta a physical

environment.

Guidelines provided regarding phyical implementation

Logical data model to create a physical database designand a set of program specifications

This module has One stage

Stage 6 Physical design

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Stage 6 Physical Design

Prepare physical design

Create physical data design

Create functional componentsimplementation map

Optimize physical data design

Complete function specification

Consolidate process data interface

Assemble physical design

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Quick Review Question

Question 1

Explain the characteristics of SSADM

Question 2Why implementation and maintenance is not

included in SSADM?

Question 3Why do you think that SSADM is highly

structured?

Documents

Week 2 - L1 - SSADM 01-12-11