With Visual Case,
you can create data
flow diagrams both complex and simple in
very little time, in an intuitive and friendly
diagramming environment.
Data flow diagrams are useful in modeling
high-level systems and processes. These
diagrams show the way in which data flows
between elements in a system and between the
system and external entities.
Typically, several data flow diagrams are
used to understand a problem. The top-level
diagram is called a context diagram and contains
one Functional Transform which represents the
entire system. The context diagram also shows
the external entities that interact with the
system. The following context diagram shows an
order entry system that interacts with customers
and shippers. The solid lines represent the
flow of data.
Data flow diagrams in Visual Case can model the
flow of control as well as the flow
of data. You can easily show and hide the
control transforms and control signals on your
diagrams at any time. A Control Transform
can be decomposed into a State Diagram.
Together, the state diagram and control
transform model the dynamic aspects of the
system.
Visual Case provides you with the following
objects with which to build data flow diagrams:
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The
external entities
are the sources and destinations of a
system's input and output. They are
objects that are not within the system, but
with which the system interacts. |
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Data storages
represent entities in the
system in which data is stored.
Examples include databases and files. |
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A
functional
transform represents an action
taken on the data. This may include a
calculation, conversion, or other task
performed. |
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A
control transform
can send and receive control signals that
help to explain the control over the data
flowing through the system. In Visual
Case you can optionally show and hide this
flow of control at any time. |
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Notes
are used to add a description on the diagram
for an object. In Visual Case, you can
connect a note to any object using a note
link. |
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Data flows
represent the movement of information
through the system.
Control signals
connect control transforms to other objects
on the diagram and represent control over
the data.
In Visual Case, you can label data flows and
control signals with any text that you like.
You can also choose between three styles of
link: segmented, direct and quadratic (shown
from top to bottom respectively).
You can also select to
show arrows at either, both or neither ends
of a link. |
Example of a Data Flow
Diagram
