This series of diagrams show different ways to model a simple
SSADM -- Structured Systems Analysis and Design Methodology
One kind of DFD
that shows how stocks are ordered, paid for, sold, and provide
income. Notice that all the processes are operating in parallel
and are connected by buffered data flows.
DFD as Use Case
A Use Case model
forces us to introduce actors. The connectivity between use cases
must not be shown. Each use case describes a way that a user gets
something out of the system -- and is not a running process.
DFD as a collaboration
expresses the interactions well but takes a lot of extra drawing
and uses non-standard stereotypes. Notice that this diagram
models only half of the original DFD.
DFD as a UML2.0 Activity Diagram
An activity diagram
shows actors as swim lanes and forces you to work out a lot
of extra detail: in particular how the external entities
operate. As a result the diagram only shows half of
the original DFD. Also notice the UML2.0 connectors that
express data flows between activities.
DFD as a UML2.0 Component diagram
In the appendix of the draft UML2.0 standard there is the
a notation that can be used to show data flows fairly precisely.
There are also a couple of useful stereotypes:
. . . . . . . . . ( end of section Expressing Data Flow Diagrams in the Unified Modeling Language) <<Contents | Index>>