A data flow diagram shows how information moves through a system and how processes transform it.
The model contains four main elements. Processes transform data. Data stores retain information. External entities provide or receive information. Meanwhile, arrows show the direction of each transfer.
A DFD focuses on inputs, outputs, and dependencies. Therefore, it helps teams identify missing information and unclear interfaces. However, it does not define the execution order of activities. Teams use activity diagrams or state machine diagrams for that purpose.
A context diagram shows the entire system as one process. In contrast, lower-level diagrams divide the system into smaller processes. As a result, teams can analyse information movement at different levels of detail.
Teams should label every process, store, external entity, and transfer clearly. Moreover, they should review the model with relevant stakeholders.
A clear data flow diagram supports requirements analysis, interface definition, functional decomposition, and system validation.
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