BIS 2030: Systems Analysis and Design
Chapter 11
Appendix: Levelling Example
The following diagrams illustrate the levelling of data-flow
diagrams. Without the original case study, the diagrams may not
make too much sense. However, if you know that it is based on an
extensive description of how a Private Hospital organisation
works, you should be able to make reasonably sense of it.
The key things to note are:
- Each lower level explains a single process from the level
above.
- All inputs and outputs to a process on the higher level
appear in the lower level
- The lower levels do not repeat information in a higher
level diagram.
- You can have as many second level diagrams as you think
necessary. Only three are thought necessary here.
Here are the diagrams:
