Question

Discuss this statement and how you might ensure that both 'to-be' software and process development overcome such model limitations to best meet business process and customer requirements. In your answer express your understanding of DFD's and process modelling and at what point you think the 'as-is' systems analysis and DFD process mapping should stop - while ensuring adequate information is gathered to deliver the 'to- be' system or process?

Answer 1

Process modelling and DFD

Process modelling is the graphical representation of the processes for which a software is being developed. Through process modelling, the structure and flow of data is organised and documented.

Data Flow Diagram or DFD is a tool that gives a visual representation of the flow of data/information in a system. DFD is widely used in software engineering and helps in process modelling. Typically, in a software development project, the system analyst would gather/elicit requirements from the users on the current (as-is) processes and then map it with the new processes (to-be) that would be put in place after the software is deployed. Data Flow Diagrams are prepared for both as-is and to-be processes.

The components of DFD are:

• Processes
• External agents representing the boundaries of the system
• Data flows - arrows in the diagram connecting the input/output from the processes, indicating the flow of data.
• Data stores - representing file or database or single entity in the system.

The as-is system analysis and DFD process mapping must stop when

• All of the processes in the diagram have been reduced to a single decision or calculation.
• The analyst has exhausted all requirement gathering questions or when users of the system do not have any more details or functions to be developed in the system.
• The entire scope of the project is covered in all the modelled processes. Out-of-scope processes need not be modelled.
• The system capabilities of the to-be software are fully mapped and users have signed them off as accepted solutions to their current processes.
• The gap analysis (differences between as-is and to-be) explaining how the changes or enhancements to the system will be implemented at each level of the DFD. Advanced DFD tools will have a feature that visually displayed the comparison of as-is diagram with the to-be diagram.