As with DFDs, there may be numerous ways to create an accurate systems flowchart. The general process is to:
- Set up and label columns, one for each internal and one for each external entity.
- Use narratives, tables of entities and activities, and DFD physical and logical diagrams for source information for the flowchart.
- Show activities proceeding from top to bottom and left to right. Keep a flowchart as clear and simple as possible while representing activities fully. Keep the flowchart to a single page, using off-page connectors when necessary.
- Use appropriate flowcharting symbols to show all processing that occurs.
- Strike a balance between clarity and clutter by using annotation judiciously and by using on-page connectors whenever flow lines might create clutter.
- Avoid crossing lines wherever possible. If you must cross lines, use a “bridge.”
- Flowchart normal routines and leave exception routines for another page of the flowchart.
- Compare the finished flowchart to narratives, activities and entities tables, and physical and logical DFDs to make sure all activities are accounted for fully.
Where are error and exception routines shown on systems flowcharts?
Drawing flowcharts requires judgment, which you can develop through practice. You have seen a number of guidelines to help you as you learn how to draw flowcharts. Before you get locked into the guidelines and the details of flowcharting, or of drawing DFDs, remember that the purpose of creating this documentation is to simplify and clarify a narrative. We draw these diagrams so that we can better analyze and understand a system. We want to portray a system’s logic and implementation accurately, and there can be many correct solutions. With practice, you can learn to use these techniques to create the most appropriate one.