What is DFD?
DFD represents the flow of data into an information system in a graphical manner. DFD is an acronym that stands for Data Flow Diagram. It is basically utilized to visualize how data flows into a system design. DFD is similar to a flowchart but in terms of detailed representation, DFD is considered to exhibit a more detailed diagram. The graphical representation presents how data flows into the system and how the exchange of data is processed.
Each function in the information system is graphically represented in details. When discussing about functions in DFD, it means each function represents a station, which is a process. Each process show in-flow of data and generates a data output. The flow shown in DFD indicates the various processes done with the input data and output data produced by the information system. DFD is an essential tool in designing software applications. It helps the designer to get a clearer picture on how to data would flow into the system.
DFD became popular and widely used by most information systems designers due to its simplicity. Its simple formalism enables information system designers to understand it is simple to utilize or employ. DFD’s starting point is an array of high-level tasks, which is performed by a system. DFD represents a range of sub-functions in hierarchical manner. Experts studying the human mind claimed that the mind easily perceives hierarchical models.
A diagram helps the brain visualize what functions will be involved in a process. DFD was developed by Larry Constantine, who happened to be the same person who developed structured design. The idea of Constantine was based on the works of Martin and Estrin. Their work is all about data flow graph model of computation. Providing DFD helps both the project sponsor and the end user to visualize how the system works or operates.
In order for a project to work and be a success, project sponsors and the end users must have a better understanding of how a system will operate. The system operation can be visualized and be understood, especially by the end users, when DFD is utilized. DFD is also useful when certain changes must be done into the system operation. Comparing the old DFD to the new one will also make it less difficult for the people involved in a project to understand the effects of each change. Comparison of the new and old data shown by the DFD will result to a more efficient system.
There are four components that are necessarily present in a DFD. Each component completes the whole system. Without at least one component, DFD model will not be complete or be able to represent the whole data flow in the system.
- External Entities ‘“ these are the factors that come outside the system that is being modeled. It shows the origin of the information.
- Processes ‘“ This is the part of the system model where input data are processed to generate output data.
- Data Flows ‘“ this part shows how data flow starting from external entities to processes and until it reaches the last station which is the data store.
- Data Store ‘“ this part of the system is where processed data is stored. Data store serves as a retrieval point when annual accounting process needs to be done.