Intro to Dataflow Diagrams
A data flow diagram (DFD) is a graphical representation of the “flow” of data through an information system, modelling its process aspects.
Often they are a preliminary step used to create an overview of the system which can later be elaborated. DFDs can also be used for the visualization of data processing.
There are made up of 4 components:
A process transforms incoming data flow into outgoing data flow.
2. External entities
External entities are objects outside the system, with which the system communicates. External entities are sources and destinations of the system’s inputs and outputs.
3. Data flows
Dataflows are pipelines through which packets of information flow. You must label the arrows with the name of the data that moves through it.
E.g. Customers logs into system
4. Data stores
Data stores are repositories of data in the system. Represents a holding area for collection of data, processes add and received data from these stores. They are sometimes also referred to as files.