Data flow model
(also data flow diagram (DFD))
Data flow model definition
A diagrammatic representation of how data moves and is used within a system. Information systems utilize data flow models to graphically depict the flow of data by explaining the processes involved in moving data from input to file storage and report generation. Inputs, outputs, storage locations, and routes are all depicted via predefined symbols like rectangles, circles, and arrows, together with brief text labels. Data flowcharts can be as basic as a hand-drawn sketch of the process or as complex as a multi-level data flow diagram (DFD) that goes into increasing detail on the data’s handling at each level. Both existing systems and proposed ones can benefit from their utilization.
Components of the data flow model
- External entity. External entities produce and consume data between the entity and the system being diagrammed. Data flows are DFD inputs and outputs. Since they’re outside the system being evaluated, these entities are usually positioned at the diagram’s edges. They represent another system or a subsystem.
- Process. All processes need DFD inputs and outputs because they convert incoming data to existing data. Instead of “process” on a diagram, this symbol is named “ship order”, depending on its function. Gane-Sarson notation uses a rectangular box containing a system location, a reference number, and a short function title. Data flow diagrams show processes from top to bottom and left to right.
- Data store. Data stores store information without performing any activities. Data stores can hold long-term files or a batch of documents waiting to be processed. Data storage input flows include data changes. Output flows are defined as data retrieved from the store.
- Data flow. Directional arrows depict the exchange of information between different nodes, including external entities, processes, and data stores. The information in question could be in any of the aforementioned formats or forms. Data flows, both incoming and outgoing, have names appended to their arrows to indicate the data type or the name of the connected process or data repository.
Benefits of a data flow model
- Helps individuals comprehend system functioning and its limits
- Shows system components clearly
- Data flow diagrams are simple enough for everyone to grasp
- Easy to understand through visualizing content in a graphical representation
- It’s a required section of the docs for the whole system
Drawbacks of a data flow model
- Can mislead system programmers
- Analysts are often denied access to DFD because they take so long to generate