Data Flow Diagram ( DFD )

Data flow diagram is usually used to show model the system’s data processing. All the processing steps are shown in the diagram through the system. They are the intrinsic part of the many analysis or design methods. They are modeled to show how the data flow through the system, how the data are flown in the system and how are they related to each other. They also depict how the data are stored at the specific locations in the system. This diagram helps showing how the data are transformed in the system.

Simple and intuitive notations are used for easy understanding showing the end-to-end processing of data. Notations used in this model represents the functional processing (represented by the rounded rectangle), data store (represented by the rectangle )and the data movement between the functions (represented via labeled arrows).

The symbols to define the DFD symbols are given in the given figure:

DFD symbols

Generally the data flow models are not supported by the UML as they were supposed to model the data. The reason behind this thing is that the DFDs focuses on the system functions and does not recognize the system objects.


Incremental Development

This is another type of model based on the idea of development initial implementation, exposing this to the user comment and evolving through the several version until adequate system has been developed. The specification, development, validation activities are interconnected rather than the separate stages with the rapid feedback across the activities.

This model is the fundamental part of the fundamental part of the agile approaches. It is thought to be better than the waterfall model for most of the business, e-commerce and the personal system. The reflection of the way that solves the problem seen clearly, we move towards the solution in a series of different phases. Using this model, the development is much and more easier. Change can be easily implemented as the development is in progress.

This model has several benefits which are enlisted as below:

  • cost of accommodation is reduced when the customer has the changing  environment.
  • easy to get the feedback from the customer on the development system.
  • rapid delivery of the software with the basic and important requirements.

Software process model

A software process model is a simplified representation of the software process. Every process model represents a process from a particular perspective and thus provides only the partial information about that process. Basically is we talk about the generic models, they are not are not definite description of the software model. Instead they are abstractions of the processes which can be used to explain the various approaches to the development of the software. To create the more and more specific software engineering process one can consider it as a framework which are ready to extend and adapt. If we talk about the various there are 3 models in software process which are listed as below:

  • Waterfall Model
  • Incremental Development
  • Re-use Oriented Software Engineering

Via ‘Software Engineering’ by Ian Somerville.