The context diagram represents the highest level of the data flow diagram. It is an abstract data flow diagram that depicts the interfaces between the system and its environment. It is shown by a circle and consists of only one process with the number 0. The process is gradually broken down into components. The components that interact with the system are shown by rectangles, and the data flow is shown by incoming and outgoing arrows for the process. Context diagrams are the origin of business computing and are used, for instance, in business application integration in order to visualize system requirements. Only if the structured analysis is expanded with a dynamic analysis can it depict control flows that are otherwise not provided.
See also Boundary Diagram