Structured Analysis and Structured Design

Presented By:-Sudeep Singh

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History of SASD

♦ Developed in the late 1970s by De Marco & Yourdon for the emergence of structured ‘or’ Modeling programming. ♦ IBM incorporated SASD into their development cycle in the late 1970s and early 1980s. ♦ Yourdon published the book “Modern Structured Analysis” in 1989. ♦ In 1990 enabled analysts to develop and modify the graphical SASD models.

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Goals of SASD ♦ Improve quality and reduce the risk of system failure. only a model \object will fail

♦ Establish specifications and complete requirements documentations. document design decision

♦ Focus on reliability, flexibility , Reusablity , Robustness , Maintainability of system. ♦ The purpose of SASD is to develop a useful, high quality information system that will meet the needs of the end user.

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Definition of 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.

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SASD Approach to Development Cycle

Existing Of Condition

Functional Architechture

System Architecture

Operational System

Build

Design

Analysis

Install and Operate

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Elements of SASD

Essential Model

Implementation Model

Environmental Model

Behavioral Model

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Essential Model

♦ Model of what the system must do. ♦ Does not define how the system will accomplish Its purpose.

♦ It is a combination of the environmental and behavioural model

Essential Model

Implementation Model

Environmental Model

Behavioral Model

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Environmental Model

♦ Defines the scope of the proposed system. ♦ Defines the boundary and interaction between the system and the outside world. ♦ Composed of: Statement of Purpose, Context Diagram, and Event List.

Essential Model

Implementation Model

Environmental Model

Behavioral Model

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Behavioural Model

Essential Model

Implementation Model

Environmental Model

Behavioral Model

♦ Model of the internal behaviour & data entities of system. ♦ Models the functional requirements. ♦ Composed of Data Dictionary , DFD , ERD, Process Specification, and State Transition Diagram.

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Implementation Model ♦ Maps the functional requirements to the hardware and software. Minimizes the cost of development & maintenance.

♦ Determine which functions should be manual vs.automated ♦ Can be used to discuss the cost-benefits of functionality With user/stakeholders. ♦ Defines the Human-Computer Interface. ♦ Defines non-functional requirements.

Essential Model

Implementation Model

Environmental Model

Behavioral Model

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Data Dictionary

= : is composed of + : and ( ) : optional element { } : iteration [ ] : selects one of the elements list | : separation of elements choice ** : comments @ : identifier for a store (unique ID)

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Entity Relationship Diagram (ERD)

• A graphical representation of the data layout of a system at a high level of abstraction • Defines data elements and their inter-relationships in the system. • Similar with the class diagram in UML. Associated Object Data Element Cardinality – Exactly 1 Cardinality – 0 or 1 Relationship Cardinality –Many Cardinality – Optional Many Sudeep singh

Summary

♦ SASD is a process-driven software analysis technique. ♦ SASD has a long history in the industry and it is very mature. ♦ It provides a good documentation for requirements. ♦ In recent years, it is widely used for developing real-time embedded system’s software. Sudeep singh

Use’s Of SASD

♦ Well-known problem domains ♦ Contract projects ♦ Real-time systems ♦ Transaction processing systems ♦ Not appropriate when time to market is short. ♦ In recent years, SASD is widely used in developing real-time embedded systems.

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Omt Vs. SASD

♣OMT ♦OBJECT MODEL ♦DYNAMIC MODEL ♦FUNCTIONAL MODEL

♣SASD ♦FUNCTIONAL MODEL ♦DYNAMIC MODEL ♦OBJECT MODEL

☻ SASD IS SIMILAR TO OMT BUT SEQUENCE ORDER IS CHANGE

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Thank’s

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