The data- flow indicates that these tasks are performed by both the user and the bank. There are various tasks performed in a bank such as transaction processing, pass book entry, registration, demand draft creation, and online help. The Level 0 DFD depicts the entire banking system as a single process. This DFD represents how a 'user' entity interacts with a 'banking system' process and avails its services. To understand various levels of DFD, let us consider an example of a banking system.

Level 0 DFD is also known as context diagram. Level 0 DFD: This shows an overall view of the system. However, these levels do not describe the system's internal structure or behavior. Note that the level of detail of process increases with increase in level(s). There are various levels of DFD, which provide details about the input, processes, and output of a system. Data movement is shown from the base of arrow as its source towards head of the arrow as destination. Data Flow - Movement of data is shown by pointed arrows.

Data Storage - There are two variants of data storage - it can either be represented as a rectangle with absence of both smaller sides or as an open-sided rectangle with only one side missing.Process - Activities and action taken on the data are represented by Circle or Round-edged rectangles.Entities are represented by rectangles with their respective names. Entities - Entities are source and destination of information data.It is more specific and close to the implementation.ĭFD can represent Source, destination, storage and flow of data using the following set of components. Physical DFD - This type of DFD shows how the data flow is actually implemented in the system.Logical DFD - This type of DFD concentrates on the system process, and flow of data in the system.For example in a Banking software system, how data is moved between different entities.DFD does not contain any control or branch elements.ĭata Flow Diagrams are either Logical or Physical. DFDs depict flow of data in the system at various levels. The flowchart depicts flow of control in program modules. There is a prominent difference between DFD and Flowchart. The DFD does not mention anything about how data flows through the system. It is capable of depicting incoming data flow, outgoing data flow and stored data. The data flow diagram is a graphical representation of flow of data in an information system. IEEE defines a data-flow diagram (also known as bubble chart and workflow diagram) as, 'a diagram that depicts data sources, data sinks, data storage and processes performed on data as nodes and logical flow of data as links between the nodes.' DFD allows the software development team to depict flow of data from one process to another.

Data flow model diagram visio