A data Flow Diagram (also called DFD) maps out the flow of information for any process or system. It shows where data comes from, which activities process the data, and whether the output results are stored or used by another activity or external entity.
A data flow diagram illustrates the movement and transformation of data between externals (entities) and processes. The output from one external or process is the input to another. The data flow diagram also illustrates the temporary or permanent repositories (referred to as data stores or terminators). These store data within a system or an organization.
The data defined should be described in a data dictionary (see technique Data Dictionary
Your roadmap for databases
Why use a Data Flow Diagram?
Replaces a laborious description/Portrays a complex process in a simple diagram
Visually represents your system and its interactions. Also illustrates connections to other systems.
Gives an overview of the information’s movements (How it enters and leaves a system, how it is transformed)
Helps to explain the logic behind the data flow within a system.
Can be used as part of system documentation.
Pinpoints its weaknesses, scope, interfaces, and boundaries
Identifies its needs
Helps with potential modifications
Can be used to analyze an existing system or model a new one
Ensures fluid communication between a system analyst and individuals
Helps to identify duplicated data elements or misapplied data elements.
May be used as a discovery technique for processes and data or as a Technique for the verification of functional decompositions or data models.
How to use a Data Flow Diagram
Data flow diagram example
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On top of the brief description of the method, access to:
- an explanation of when and how to use it,
- a practical example,
- tips and recommendations for use,
- downloadable checklists and templates,
- references for further reading,