ITM 410 Lecture Notes - Lecture 3: Data Flow Diagram

• School: Ryerson University
• Department: Information Technology Management
• Course: ITM 410
• Professor: Helen Chen

Document Summary

Context dfd top level diagram of a system depicing the system aciviies as a single bubble. All eniies are engulfed in on bubble interacing with other external eniies. Physical dfd shows how the system"s internal and external eniies interact showing where, how and by whom informaion lows throughout the system. Logical dfd: graphical representaion of system processes, speciically what aciviies are being performed. Include eniies that perform one or more processing aciviies. Include only normal process rouines, not excepion rouines; assuming everything goes smoothly. Include in the process documentaion all aciviies described in the narraive; nothing else: for clarity, draw each low in and out of the store; label and describe each low with a number or a descripion. If the store is necessary (logically), in case of delays between processes, indicate the data store. In physical data low diagrams, include the data store even if it is not menioned in the.