5/26/2009
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Chapter 8
Structuring System
Requirements: Process Modeling
Chapter 8
Structuring Systems Requirements: Process
Modeling
Understand the logical modeling of
processes by studying examples
of data flow diagrams (DFDs).
Draw data flow diagrams following
specific rules and guidelines that
lead to accurate and well-
structured process models.
Decompose data flow diagrams
into lower-level diagrams.
Balance higher-level and lower-level
data flow diagrams.
Explain the differences among four
types of DFDs: current physical,
current logical, new physical, and new
logical.
Use data flow diagrams as a tool to
support the analysis of information
systems. Discuss process modeling for
electronic commerce applications.
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Process Modeling Requirements structuring
Requirements structuring is the second of the
three primary analysis phases.
This chapter introduces us to two methods
useful for structurin
g
requirements:
g
– Process modeling
– Logic modeling
Requirements structuring
The focus of this session will be on a tool
analysts use to structure information – data flow
diagrams (DFDs).
DFD allow us to model how data flow throu
g
h
g
an information system, the relationship among
the data flows and how data to be stored at
specific locations.
Requirements structuring
DFD also show the processes that transforms
data. Because DFD concentrates on the
movement of data between processes, the
diagrams are called process models.
There are two important concepts related to data
flow diagrams:
– balancing
– decomposition
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