16
According
to
Whitten
[4],
we
shouldn’t
confuse
between
DFD
and
flowchart.
They
are very different. 3 differences between DFD and flowchart:
1. Processes on DFDs can operate in parallel (at-the -same -time)
o
Processes on flowcharts execute one at a time
2. DFDs show the flow of data through a system
o
Flowcharts show the flow of control (sequence and transfer of control)
3. Processes on one DFD can have dramatically different timing
o
Processes on flowcharts are part of a single program with consistent timing
2.1.4.2 DFD Components
There are 3 widely used of
DFD Components according to Whitten [4]:
1. Process. A process
is work performed on, or
in response to,
incoming data
flows
or conditions.
Figure 2. 8 Process
(Source: Whitten, Jeffry L., Bentley,
Lonnie D., and Dittman, Kevin C. 2000. System Analysis and Design
Methods)
2. Data Store . A data store is an inventory of data.
Frequently implemented as a file or database.
A
data
store
is
“data
at
rest”
compared
to
a
data
flow
that
is
“data
in
motion.”
Almost always one of the following:
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