Data Flow Diagrams
Download 259 Kb.
|
1.1 CASE toolsFor many ways of developing and implementing new systems, software is available to help the systems analyst produce what is required. This software is called a CASE tool. CASE stands for Computer Aided Software Engineering. Data Flow Diagrams are usually produced using a CASE tool although they can be produced simply with a pencil and paper. The diagrams shown in this unit were developed using SELECT SSADM Professional version 4.1.1. Using a CASE tool for construction of the DFDs has many advantages. It is not just a drawing tool. Firstly the CASE tool will not allow a non-standard use of notation for all the items in the diagrams. Secondly it applies some rules so that designing the diagrams prevents the users from making connections between the different items that should not be allowed. There is also some checking that may be invoked to alert the designer to some potential errors. As we will see the CASE tool helps to check that the DFDs are consistent with other views of the system which require diagrams that may also be drawn with the CASE tool. You would find it helpful to become familiar with a CASE tool to practice some of the example activities in this unit.
Download 259 Kb. Share with your friends:
|