Question

What are DF Diagrams , and how they help project managers in their job?

Answer 1

As you can see, is a data flow diagram a diagram that shows the dataflow in an application.

At the highest level you have the context diagram that can be represented as:

          +-------------+ input --> | Application | --> output           +-------------+  You can zoom into the function to show detailed dataflow:            +-------+      +--------+     +----------+ code  --> | lexer | -->  | parser | --> | treetool | --> grapical representation           +-------+      +--------+     +----------+               |              ^                 ^               |              |                 |               |              V                 |               |    ================            |               +--> | symbol table | -----------+                    ================ 

As you see, there are functions and data stores. Functions can change the data and datastores are used to store and retrieve the data.