Data flow diagram

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A Data flow diagram (DFD) is a graphical representation of the flow of data through an information system. A DFD shows the flow of data from data sources and data stores to processes, and from processes to data stores and data sinks. DFDs are used for modelling and analyzing the flow of data in data processing systems, and are usually accompanied by a data dictionary, an entity-relationship model, and a number of process descriptions.

Contents 1 Types of structure 2 Types of flow 3 Building blocks 4 Data flow diagram levels 5 See also

[edit] Types of structure

Simple structure

Iteration

Manchester architecture

[edit] Types of flow

Condition type graph

if condition

while loop

Computation involving several nodes

[edit] Building blocks

Switch type node	Merge type node	Computational node	Firing node
Data flow note	Notation

[edit] Data flow diagram levels

Context level

Level 0 Data flow diagram for the same system.

Level 1 Data flow diagram showing the "Process Enquiry" process for the same system.

[edit] See also

• Flowchart