Notesale: Turn your study into money

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CREATING DFD
Principle for Creating Data Flow Diagrams
the principle for creating a DFD is that one system may be disintegrated into subsystems, which in
turn can be disintegrated into subsystems at a much lower level, and so forth
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In this process or activity the input data is processed
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Each process in a DFD characterizes an entire
system
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Once
entered the data flows between processes, then the processed data is produced as an output or a
result
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The
technique starts w ith an overall picture of the business and continues by analyzing each of the
functional area of interest
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The technique exploits a method called top-down expansion to conduct the analysis in a targeted
way
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1
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In the diagram's
name box (at the top left corner), enter Context and press ENTER
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We'll now draw the first process
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Name
the new process System
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Next, let's create an external entity
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Drag the resource
icon Bidirectional Data Flow --> External Entity to the left and release your mouse to create one
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Name the new external entity Customer
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Now we'll model the database accessed by the system
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Then release your mouse to create a new data store
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Name the new data store Inventory
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Create two more data stores, Customer and Transaction, as shown below
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