Difference between data flow diagram and use case diagram?

Answer 1

Use Cases describe a sequence of actions. Those actions must provide the measurable value to an actor. It is represented by horizontal ellipse.

Data Flow Diagrams have been around for about thirty years. There are a number of newer

techniques available, and it might seem that one of these would be a better alternative to the

DFD. In our experience, even though technology has changed dramatically, what you are

looking for when modeling business processes hasn't changed much at all.

If you are developing requirements for an information system, you need to discover and

document:

ü overall process flow

ü activities being performed

ü inputs & outputs to the activities

ü events that trigger the activities

ü who performs the activities

ü where the activities are performed

ü where information is stored

ü who supplies information

ü who needs to receive information.

Answer 2

DFD are just the representation of data flow in a project from one part to another .

UML diagrams are for to depict the picture of project . UML are very useful to understand about the project just by having a glance on these diagrams.