Logical & Physical DFDs.

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Logical & Physical DFDs

LOGICAL AND PHYSICAL DFD

DFD’S considered so far are called logical DFDs.

A physical DFD is similar to a document flow diagram. It specifies who does the operations specified by the logical DFD. Physical DFD may depict

physical movements of the goods. Physical DFDs can be drawn during fact gathering phase of a life cycle.

PHYSICAL DFD FOR ENCASHING CHEQUE
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LOGICAL DFD FOR CHEQUE ENCASHMENT

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REFERENCES

1. This module is based on Chapter 7 of Analysis and Design of information systems, V.Rajaraman, Prentice Hall of India, New Delhi, 2002.

2. Ian Sommerville, “Software Engineering”, 5th Edition, Addison- Wesley, 1996, has a brief discussion of Data Flow Models on pp.101 to 103.

3. T.DeMarco, “Structured Analysis and System Specification”, Yourdon Press, 1978. this book written by the original developer of DFD modeling is a well written book. It is a good reference book.

4. E.Yourdon, “Modern Structured Analysis”, Prentice Hall of India, New Delhi, 1996. Chapter 9 (pp.139 to 187) is a good treatment of Data Flow Diagrams. All the topics covered in this module are discussed in this chapter.

5. Hoffer, J.A., George, J.F. and Valacich J.S., “Modern Systems Analysis and Design”, 3rd Edition, Pearson Education Asia, New Delhi, 2002. Chapter 8 (pp.241 to 271) has a good treatment of DFDs with a running example of a quick service restaurant. Different types of DFDs and logical checking of DFDs are discussed well.

6. K.E.Kendall and J.E.Kendall, “Systems Analysis and Design”, 5th Edition, Pearson Eduation Asia, New Delhi, 2003. Chapter 9 is devoted to Data Flow Diagrams (pp.241 to 285). Has a number of problems at the end of the chapter which are quite interesting.

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