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Lesson#23
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Benefits of Good System Design
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Benefits of Good System Design
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Better understanding by
the developer of the system. A properly designed system helps in
elaborating and understanding refined aspects of system.
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System development
becomes efficient. An error free designed system saves development time
since it helps in understanding without discussion.
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A well designed system
also helps in early detection of problems in critical areas, if any.
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Better quality of
reporting formats. Modifications can be made easily in the system.
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Little maintenance is
required in the operations phase.
23.1 System Analysis & Design Methods
Two approaches are followed for system analysis and design
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Structured analysis and
design – Which includes various tools, such as.
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Flowcharting
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Data Flow diagram
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ERD
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Object oriented analysis
and design
23.2 Structured Analysis and Design
Structured analysis and design follows a set of good practices
and generally accepted standards. Proper
documentation of the system is made by following standard rules.
23.3 Flow Chart
"A schematic representation of a sequence of operations as in a
manufacturing process or computer
program."
Introduction
Flowchart is the most commonly used design and analysis
technique. The diagrammatic presentation gives a
quick understanding of the business processes and flows.
Symbols
Although there are many symbols used proposed by various
standards, but we would discuss some of the
most commonly used symbols. Understanding symbols representing
functions, flows, etc may be more
readily understood by those who have some knowledge of the
symbols. From a technical or point
of view, we have to know what symbols are used for various
functions, etc.
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Terminator
Only one flow line is used in
conjunction with terminator symbol.
Arrow
The usual direction of the flow of a
procedure or system is from left to
right or top to bottom.
or
Ensure that the flowchart has a
logical start and finish.
Decision
Only one flow line should enter a decision
symbol, but two or three flow lines, one for
each possible answer, should leave the
decision symbol
Process
Only one flow line should come out
from a process symbol.
<0 >0
=0 <0 >0
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Input / Output
Used whenever data is into the flowchart or
displayed from the flowchart. A single flow
line enters and a single line exits.
Off-Page Connector
Use to connect remote flowchart portion on
different pages. One flow line enters or
exits.
Single Document
Predefined Process
This represents a named process
consisting of one or more operations
or program steps specified elsewhere
Connectors
If the flowchart becomes complex, it
is better to use connector symbols to
reduce the number of flow lines.
Avoid the intersection of flow lines if
you want to make it more effective
and better way of communication.
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Good Practices
Like every other methodology, flow charts also have a set of
recommended practices for flow charts:
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In drawing a proper
flowchart, all necessary steps that are a part of process should be listed out
in
logical order.
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The flowchart should be
clear, neat and easy to follow. There should not be any room for
ambiguity in understanding the flowchart.
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It is useful to test the
validity of the flowchart.
Input / Output
• Used whenever data is entered
into the flowchart or displayed
from the flowchart.
• A single flow line enters and a
single line exits. |
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