Final answer:
To develop a DFD for a system request and requirements, start with a context diagram, then create a level 0 DFD to show the processes and data flow. To decompose a process, break it down into sub-processes in a lower-level diagram.
Step-by-step explanation:
A context diagram in data flow diagram (DFD) shows the interactions between a system and its external entities. It provides a high-level view of the system and shows the input and output data flows. To develop a context diagram for the given system request and requirements, you can identify the main system being analyzed and the external entities involved. Then, depict the system as a single process surrounded by the external entities, with arrows representing the data flow between them.
A level 0 DFD expands on the context diagram to show the different processes within the system and how they are connected. Each process is represented by a circle or square, indicating a function or transformation that occurs within the system. The processes are connected by arrows representing the data flow between them. To draw a level 0 DFD, you can analyze the main process from the context diagram and decompose it into its sub-processes to show the overall flow of data within the system.
To decompose a process from a level 0 DFD to a lower-level diagram, you can further break down the process into its sub-processes or steps. Each sub-process can be represented by a separate process symbol in the lower-level diagram, with arrows indicating the data flow between them. This decomposition allows for a more detailed analysis of the specific processes within the system.