Data Flow Diagrams
What is DFD (Data Flow Diagram)?
Data flow diagram is a method for implementing the information or software system graphically. Data Flow Diagrams shows the whole process of transferring data from input files to end of the output file generation. Data Flow Diagrams can be divided into two parts. They are,
1. Logical
2. Physical
Logical Data Flow Diagrams are been used to describe flow of the data through a system to preform certain functionality of a process. Physical Data Flow Diagrams used to implement the logical data flow.
Data Flow Diagrams represent the functions or processes which capture, manipulate, store and distribute data between a system and its environment and between components of a system. The DFD structure allows you to start from an overview and extend it to a hierarchy of detailed diagrams. The visual representation makes it a good communication tool between the user and the designer of the system. Due to following reasons, DFD has been often used:
· Logical information flow of the system
· Determination of physical system construction requirements
· Simplicity of notation
· Establishment of manual and automated systems requirements
There are certain symbols used to draw Data Flow Diagrams.
Explaining how the DFD differ from UML designs.
As we know that the application developers require a blueprint on the model in order to develop a system not with the imagination. There are certain standards and techniques that are necessary to produce these models and systems without ambiguity. Data Flow Diagrams and UML diagrams are one of those techniques that can be used to perform. But both of these techniques are not at the same level and do not serve the same purpose.
DFD is a technique to visualize certain aspects of a conceptual system or application. These elements are,
· Source of data
· Flow of data
· States of data
· Destination of data
· Manipulation of data
Depending on the intended audience and the technically declined audience, DFD can be either high level or low level . A data flow diagram (DFD) is a graphical representation of the “flow” of data through an information system, modelling its process aspects.
UML(Unified Modeling Language) is a modeling notation comprising of numerous techniques used in Object-Oriented Data Modeling. This technique includes
· class diagrams
· use case diagrams
· activity diagrams
· component diagrams
· statechart diagrams
UML diagrams are efficient because they are capable of representing static and dynamic conditions in a system.
