Final presentation of tools and techniques of structure analysis (Management Information System) PPT Slides

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Tools and TechniquesOf

Structured Systems Analysis and Design

(SSAD)

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MEMBERS ROLL NO

• Himansu ojha

• Rohan naik 011179

• Ajay nandkumar

• Rohan yadav

• Nishant jadav

• Manvir singh sohal

• Gurpreet singh jhuman

• Sukesh nagurkar

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Acknowledgement

• We would like to thank M/s Priya Vij for giving us this opportunity.

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Structured Systems Analysis and Design

Structured Systems Analysis and Design (SSAD) is a systems approach to the analysis and design of information systems. SSAD was produced for the CCTA, a UK government office concerned with the use of technology in government, from 1980 onwards.

System design methods are a discipline within the software development industry which seek to provide a framework for activity and the capture, storage, transformation and dissemination of information so as to enable the economic development of computer systems that are fit for purpose.

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Objectives

• Improvements in communication.

• Ensure the maintainability of the system to be analyzed.

• Useful tools for representing the system.

• Must be able to effectively partition a complex problem.

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Benefits of SSAD

• Usability

• Respond to changes in the business environment

• Effective use of skills

• Better quality

• Improvement of productivity

• Cuts costs

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Disadvantages of SSAD

• SSAD puts special emphasis on the analysis of the system and its documentation. This causes the danger of over-analysing, which can be very time and cost consuming.

• Due to various types of description methods, checks of consistence cannot be carried out.

• Especially with large systems, the outline diagram can become very unclear, because all relevant data flows have to be included.

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SSADM Tools

• Data Flow Diagram (DFD).

• Data Dictionary.

• Structured English.

• Decision Trees.

• Decision Tables.

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Data Flow Diagram:

• Data Flow Diagram(Bubble Chart) is a graphical representation of the logical flow of data.

• It help in expressing the system’s requirements in a simple and understandable form the and Contains 4 graphic symbols.

• It clarify the system requirement and indentify major transformations that will become program in system design .

• Still used today to document business and/or other processes.

• Data flow refers to the movement of data through a system from entry to destination

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Data Flow Diagram: Signs

1.Symbol: Square Meaning: External Agent. Description: A source/destination of system data

2.Symbol: Arrow Meaning: Data FlowDescription: Pipeline through which the data flows.

3.Symbol: Oval• Meaning: Process• Description: A series of one or more steps that converts inputs to outputs

• 4.Symbol: Open rectangleMeaning: Data Store.Description: Data at rest, usually a file or database table

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Rules for drawing the DFD:

• Process should be named and numbered .• Name should represent the process .• The direction of flow is from top to bottom and from left to

right .• Sources cannot leak data directly to a data store .• The name of data stores, sources and destinations are written

in capital letter . Process and data flow names have the first letter capitalized. 

cont…..

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DATA DICTIONARY

Meaning• Data dictionary contains definition of “DATA”, used in system• It contains accurate definition of all DFDs, data elements & data

structure• A data dictionary contains a list of all files in the database, the number

of records in each file, and the names and types of each field.

• Data dictionaries do not contain any actual data from the database, only book keeping information for managing it. Without a data dictionary, however, a database management system cannot access data from the database

• The definitions of all schema objects in the database (tables, views, indexes, clusters, synonyms, sequences, procedures, functions, packages, triggers, and so on)

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Features Of Data Dictionary:

• Structured repository of data

• Reference Work of data

• Support Documentation

• Improve Communication

• Describe Interrelationship

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Data Dictionary Contains Mainly Three Items:

• Data element

• Data structure

• Data flow and data store

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Structured English

• Structured English is the use of the English language with the syntax of structured programming.

• structured English aims at getting the benefits of both the programming logic and natural language. Program logic helps to attain precision while natural language helps in getting the convenience of spoken languages.

cont…..

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Structured English consists of the following elements:

• Operation statements written as English phrases executed from the top down

• Conditional blocks indicated by key words such as IF, THEN, and ELSE

• Repetition blocks indicated by key words such as DO, WHILE, and UNTIL

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Guidelines when writing Structured English

• Statements should be clear and unambiguous.

• Use one line per logical element.

• All logic should be expressed in operational, conditional, and repetition blocks.

• Logical blocks should be indented to show relationship.

• Keywords should be capitalized.

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Example

• If customer purchase > Rs 1000

• Then give 10% discount

• Else do not provide any discount

• End- if

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Decision tree

• A decision tree is a decision support tool that uses a tree-like graph or model of decisions and their possible consequences.

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A Decision Tree Consists of 3types of Nodes:-

1. Decision nodes – commonly represented by squares.

2. Chance nodes - represented by circles.

3. End nodes - represented by triangles.

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Advantages

• Are simple to understand and interpret.• Have value even with little hard data.• Can be combined with other decision techniques.

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Decision table

• Decision table are a precise yet compact way to model complicated logic. Decision tables, like if-then-else and switch-case statements, associate conditions with actions to perform.

• A Decision table represents all possible conditions, actions. The table is divided into columns which contain the conditions, actions and rules.

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Decision table Structure

The four quadrants• Conditions• Condition alternatives• Actions• Action entries

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SSADM Techniques

The 3 most important techniques that are used in SSADM are:

• Logical Data Modelling.• Data Flow Modelling.

• Entity Behaviour Modeling.

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Logical Data Modelling

This is the process of identifying, modelling and documenting the data requirements of the system being designed.

The data are separated into entities (things about which a business needs to record information) and relationships (the associations between the entities).

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Data Flow Modeling

• This is the process of identifying , modeling and documenting how data moves around an information system . Data Flow Modeling examines processes (activities that transform data from one form to another), data stores(the holding areas for data), external entities (what sends data into a system or receives data from a system), and data flows (routes by which data can flow).

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Entity Behaviour Modelling

• This is the process of identifying , modeling and documenting the events that affect each entity and the sequence in which these events occur.

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How is SSADM Structured

• SSADM consists of 5 main modules , which are in turn broken down into a complex hierarchy of stages, steps and tasks.

• Feasibility Study.

• Requirements Analysis.

• Requirements Specification.

• Logical System Specification.

• Physical Design.

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