CS507 Assignment No. 3 solution
Monday, June 06, 2011 Posted In CS and IT Edit ThisQuestion:
Assume the working phenomenon of www.amazon.com, while considering their shopping cart mechanism in mind; draw the ‘Data Flow Diagram’ for a specific department with respect to a customer?
Hint: Visit www.amazon.com and consider acceptable assumptions regarding online sales mechanism. Use Microsoft Word or Microsoft Visio for drawing DFD.
Note: You have to draw the complete diagram with proper labeling
Last Date 9June, 2011
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Solution:
DFD specifies only what processes are performed and not how they are performed it is easily understood by a nonprogramming user.
Context Level Diagram:
A diagram giving an entire system’s data flows and processing with a single Process (circle) is called a context diagram. A context diagram is expanded into a number of inter-related processes. Each process may be further expanded into a set of inter-connected sub processes. This procedure of expanding a DFD is known as levelling.
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Data Flow Diagram"A data flow diagram (DFD) is a graphical representation of the "flow" of data through an information system."
The purpose of data flow diagrams is to provide a linking bridge between users and systems developers.
The data flow diagrams are:
• Graphical, eliminating thousands of words;
• Hierarchical, showing systems at any level of detail; and
They have less jargon, allowing user understanding and reviewing. Data flow diagrams facilitate users to understand how the system operate. DFD’s also help developers to better understand the system which helps in avoiding delays in proper designing, development, etc. of projects.
Rules for DFD’s
The DFD as an analytical tool follows certain rules. These rules help in achieving the level of standardization.
• There should be no black holes, gray holes, miracles.
• Do not leave things unlabeled
• the DFD should not include data flows that are unassociated with the process
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Solution:
DFD specifies only what processes are performed and not how they are performed it is easily understood by a nonprogramming user.
Context Level Diagram:
A diagram giving an entire system’s data flows and processing with a single Process (circle) is called a context diagram. A context diagram is expanded into a number of inter-related processes. Each process may be further expanded into a set of inter-connected sub processes. This procedure of expanding a DFD is known as levelling.
:::::::::::::::::::::::::::::::::::::::::::::::::
Data Flow Diagram"A data flow diagram (DFD) is a graphical representation of the "flow" of data through an information system."
The purpose of data flow diagrams is to provide a linking bridge between users and systems developers.
The data flow diagrams are:
• Graphical, eliminating thousands of words;
• Hierarchical, showing systems at any level of detail; and
They have less jargon, allowing user understanding and reviewing. Data flow diagrams facilitate users to understand how the system operate. DFD’s also help developers to better understand the system which helps in avoiding delays in proper designing, development, etc. of projects.
Rules for DFD’s
The DFD as an analytical tool follows certain rules. These rules help in achieving the level of standardization.
• There should be no black holes, gray holes, miracles.
• Do not leave things unlabeled
• the DFD should not include data flows that are unassociated with the process
