SADT stands for Structured Analysis and Design Technique which is a
trademarked and copyrighted by Softech Inc. A SADT model is a
collection of diagrams organised in a tree structure. Each SADT
diagram is composed of Boxes (representing activities) connected by
Flows (arrows) representing flows of materials, data or information.
The SADT sheet provides the three basic components required for
drawing SADT diagrams: Activity/Data Flow, Activity/Data box, and Flow
Annotation.
The activity/data flow can be one of several styles, including Normal,
Import Resource, Imply Resource, Dotted Arrow, or with Disabled
Arrows. The default is Normal but can be changed in the Object
Defaults window (double click the Activity/Data Flow button).
Figure 24.9:
A sample of the SADT digram objects.
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Flows have different roles in relation to the activities. The middle
mouse button (or control right click on Windows) is used to add or
remove segments.
The default flow is Vertical-Horizontal-Vertical. It is sometimes
useful to do a bit of middle mouse button clicking to build a
Horizontal-Vertical-Horizontal variant which can then serve for
copy-and-paste in your diagram. A non Vertical-Horizontal-Vertical
flow will be shown in black instead of the default grey. While this is
not in the original SADT specification it is often handy to untangle a
heavily loaded sheet (with more than 4 or 5 functions--though these
sheets should be avoided).
Connections points can be added to or removed from the sides of an
SADT box by clicking the middle mouse button. Function identifier
(A0, A1, etc.) can be changed by opening the box properties. The
associated function (the contents of the box) is changed by simply
selecting the box and typing any text.
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