System Analysis and Design
System Implementation
- Mr. Ahmad Al-Ghoul
learning Objectives
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Explain the steps in Drawing a
Structure Chart
Describe other structured
development tools
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Structure Chart Example
 Sample of a sales promotion policy with logical rules,
and a structured English version of the policy.
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Structure Chart Example
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The Figure below shows the initial design for a structure chat based
on the sales promotion policy that was described in structured English
in the previous slide.
The module named Process Sales Promotion Actions is a control
module with four subordinate modules.
The curved arrow indicates that, read customer record is repeated
until finished all customer records
Data couples and control couple have not been added
The loop symbol, represents repetitive processing.
Initial design for a structure chart based on the sales promotion policy
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Drawing a Structure Chart
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If you used a structured analysis method,
your structure charts will be based on the
DFDs you created during data and process
modeling, you should review data flows and
the data dictionary
If you used Object-Oriented analysis method,
your structured charts will based on object
models, you should review the class diagrams
and object relationship diagrams
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To draw a structure chart you must follow
the four following steps
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Step 1: Review the DFDs
Review all DFDs for accuracy and completeness,
especially if changes have occurred since the
system analysis phase
 If object models also were developed, you should
analyze them to identify the objects, the methods,
and the relationships among the objects.
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A method is similar to a functional primitive, and requires
code to implement the necessary actions
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Steps in Drawing a Structure Chart
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Step 2: Identify Modules and Relationships
Transform functional primitives or object methods
into program modules
 Each DFD level represents a processing level
 You would work your way down from the context
diagram to the lower level diagram, identifying
control modules and subordinate modules, until
you reach functional primitives
 If more cohesion is desired, you can divide
processes into smaller modules that handle a
single task
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Steps in Drawing a Structure Chart
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Step 3: Add Couples, Loops, and Conditions
If you working with DFDs, you can review the data
flows and the data dictionary to Identify the data
elements that pass from one module to another
 Add control couples where a module is sending a
control parameter, or flag, to anther module
 Add loops and condition lines that indicate
repetitive or alternative processing steps
 If you used Object-Oriented analysis, you can
review the class diagrams and object relationship
diagrams.
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Steps in Drawing a Structure Chart
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Step 4: Analyze the Structure Chart and the
Data Dictionary
Ensure that the chart reflects all previous
documentation and that the logic is correct
 You should check each process, data element, or
object method
 You should determine that modules are strongly
cohesive and loosely coupled
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Structure Chart Example
We studied this diagram before in the analysis chapter,
diagram 0 consist of 3 functions FILL ORDER, CREATE
INVOICE, and APPLY PAYMENT
Level 1 DFD for process1, shows details of the FILL ORDER
process in the order system.
The FILL ORDER consists of three processes, VERIFY ORDER,
PREPARE REJECT NOTICE, and ASSEMBLE ORDER
DFDs for a sample Order System. The top DFD is Diagram 0; under it
is Diagram 1.
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Structure Chart Example
we take our way down from the context digarm to the lower level diagram so the
first control module is order system module you can see, order system module is a
control module with a condition line that triggers one of three subordinate modules
Then you can see the fill order control module, fill order module is a control
module with a condition line
Also you can see a fill order module sends a rejected order flag to prepare reject
notice module
A structure chart based on the Order System DFDs shown in the
pervious slide.
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Structured Application
Development
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Other Structured Development Tools
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Program Flowcharts
The pictorial representation of the programs or the
algorithm is known as flowcharts.
 It is nothing but a diagrammatic representation of
the various steps involved in designing a system.
 Program flowcharts graphically represent the logic
and interaction between program modules
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Program Flowcharts
 A flowchart consists of a set of
‘flowchart symbols’ connected by
arrows. Each symbol contains
information about what must be
done at that point & the arrow
shows the ‘flow of execution’ of
the algorithm i.e. the arrows
show the order in which the
instructions must be executed.
The purpose of using flowcharts
is to graphically present the
logical flow of data in the system
and defining major phases of
processing along with the various
media to be used.
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Flow chart example
 consider the rules associated with paying commission in
company X. showing below in structured English
For each commission earned
If extra bonus equal y
If payment total is greater than 50000$
Add 2% to commission percent
Output special letter
Output award list
Else
Add 1% to commission percent
Output award list
Else
If payment total is greater than 50000$
Add 1% to commission percent
Output special letter
Calculate commission = commission percent times payment
total
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The Figure above shows A program flowchart shows the logic needed to
calculate commissions and perform related tasks based on the structured
English in the previous slide
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Other Structured Development Tools
 Pseudocode: Pseudocode is a technique for representing
program logic.
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Pseudocode can be used to describe an algorithm.
Although pseudocode resembles structured English (SE) in
using a restricted subset of English, it may be coded and
more closely resemble a programming language.
Whereas SE is a useful tool when analysts communicate
with end – users, pseudocode is oriented towards analyst
– programmer communication, describing program logic,
using program construction.
Using pseudocode, a system analyst or a programmer can
describe program actions they can implement in any
programming language
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Pseudocode example
When comparing between the structured English example and the pesudocode
one you can notice that the pesudocode is programmer oriented you can see
statements like open files read commission record, the end if’s, print statement,
close program and end the program
An example of pseudocode that documents the logical steps in the sales
commission SE shown in slide number 14.
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Sequence Summary
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Typically, you follow four steps when you create a
structure chart
You review DFDs and object models to identify the
processes and methods, identify the program modules and
determine the control-subordinate relationships, add
symbols for couples and loops, and analyze the structure
chart to ensure that it is consistent with your system
documentation
flowchart is nothing but a diagrammatic representation of
the various steps involved in designing a system.
A flowchart consists of a set of ‘flowchart symbols’
connected by arrows.
Pseudocode is a technique for representing program logic.
pseudocode is oriented towards analyst – programmer
communication, describing program logic, using program
construction.
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Sequence Summary
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In this Sequence we have
Explained the steps needed to draw a
structure chart
 Defined and explained program flowcharts
 Defined and explained Pseudocode
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Reference
[1] System Analysis and Design, Sixth
Edition
Authors: Gary B. Shelly, Thomas J.
Cashman and Harry J. Rosenblatt
Publisher: SHELLY CASHMAN SEWIES.
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