System Analysis and Design
System Analysis
- Mr. Ahmad Al-Ghoul
Learning Objectives
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Create a data dictionary entries for
data flow
Create a data dictionary entries for
data stores
Create a data dictionary entries for
process
Create a data dictionary entries for
entities
Describe a data dictionary reports
Describe where to use data dictionary
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Data Dictionary
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Data flows & Data stores
Data flows are paths along which data travels &
Data stores are places where data is stored until
needed. So we can say that Data flows are Data
structures in motion & Data stores are Data
structures at rest.
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Data Dictionary
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Documenting the data flow
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Each data flow should be defined with descriptive
information and it's composite structure or elements
Include the following information:
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Data flow name or label: the data flow name as it appears
on the DFD.
Alternate names: aliases for the DFD data flow names.
Description: describes the data flow and its purpose.
Origin: the DFD beginning, or source, for the data flow; the
origin can be process, a data store, or an external entity
Distention: the DFD ending points for the data flow; the
destination can be a process, a data store, or an external
entity.
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Data Dictionary
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Documenting the data flow
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Type: an indication of whether the data flow is a
record entering or leaving file or a record containing a
report, form, or screen. If the data flow contains data
that are used between processes, it is designated as
internal
Record: each data flow represent a group of related
data elements called a record or data structure.
Volume and frequency: describes the expected
number of occurrence for the data flow per unit of
time, This could be records per day or any other unit
of time
An area for further comments about the data flow
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Data Dictionary [2]
Data Flow Example
Name
ORDER
Description
Contains customer order information and is used
to update the customer master and item files and
to produce an order record.
Source
CUSTOMER External Entity
Destination
Process 1.1, VERIFY ORDER
Type
Screen
Data Structure Order Information
Volume/Time 10/hour
Comments
An order record contains information for one
customer order. The order may be received by
mail, fax, or by telephone.
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Data Dictionary
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Data store
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Data flow base elements are grouped together and a
data store is created for each unique group
Data stores may be determined by analyzing data
flows
Since a data flow may only show part of the collective
data, called the user view, you may have to examine
many different data flow structures to arrive at a
complete data store description
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Data Dictionary
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Documenting the data store
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Data store name or label : the data store name as it
appears on the DFD, alternate names aliases for the
DFD data store name
Description: describes the data store and its purpose.
Input data flows : the standard DFD names for the
data flows interring the data store
Output data flows: the standard DFD names for the
data flows leaving the data store.
Record: the record name in the data dictionary for the
data store.
volume and frequency: describe the estimated
number of records stored in the data store and how
frequently they are updated
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Data Dictionary
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Documenting the Processes
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Process name or label: the process name as it appears on the
DFD
Description : a brief statement of the process general purpose
Process number: a reference number that identifies the process
and indicates relationships among the various levels in the
system
Input data flows: the standard DFD names for the data flows
entering the process
Output data flows: the standard DFD names for the data flows
leaving the process
Process description this section is filled only if the process is a
functional primitive. For functional primitives the process
description documents the processing steps and business logic
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Data Dictionary
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Documenting the Entities
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By documenting all entities, the data
dictionary can describe all external entities
that interact with the system
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Entity name: the entity name as it appears on the DFD.
Description: describe the entity and its purpose.
Alternate name(s): any aliases for the entity name.
Input data flows: the standard DFD names for the input
data flows to the entity.
Output data flows: the standard DFD names for the data
flows leaves the entity.
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Data Dictionary
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Data Dictionary Reports
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A data dictionary is created when the system is
developed, and is updated constantly as the system is
implemented, operated, and maintained
Data dictionary documents the relationships among
the system components
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Many valuable reports can obtain from data dictionary
including
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An alphabetized list of all data elements by name
A report describing each data element and indicating the user
or department that is responsible for data entry, updating, or
deletion
A report of all data flows and data stores that use a particular
data element
Detailed reports showing all characteristics of data elements,
records, data flows, processes, or any other selected item
stored in the data dictionary
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Data Dictionary
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Using the Data Dictionary
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Data dictionaries may be used to
Create reports, screens, and forms
 Generate computer program source code
 Analyze the system design for completion and to
detect design flaws
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Sequence Summary
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Data flows are paths along which data travels & Data
stores are places where data is stored until needed.
Each data flow should be defined with descriptive
information and it's composite structure or elements
Data flow base elements are grouped together and a
data store is created for each unique group
By documenting all entities, the data dictionary can
describe all external entities that interact with the
system
Considering documentation in one location allows you to
verify the information system’s accuracy and consistency
more easily and generate a variety of useful reports
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Sequence Summary
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In this Sequence we have
 Defined the terms data flow and data store
 Explained how to create a data dictionary entries for
data flow
 Explained how to create a data dictionary entries for
data stores
 Explained how to create a data dictionary entries for
process
 Explained how to create a data dictionary entries for
entities
 Described a data dictionary reports
 Described where to use data dictionary
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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.
[2] system analysis and design, sixth edition
Authors: Kenneth E. Kendall and Julie E. Kendall
Publisher: Prentice Hall
[3] Modern Systems Analysis and Design Third Edition
Authors: Jeffrey A. Hoffer , Joey F. George, Joseph S. Valacich
Publisher: prentice hall
[4] System Analysis and Design, 3rd Edition
Authors: Dennis, Wixom, & Roth
Publisher: John Wiley & sons
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