All the items that are listed could have some impact on the SDLC (Software Development Life Cycle), depending upon what type of information they contained. I use all the items all the time. However one should note that the information contained in each of the ones listed may be dated, obsolete or incorrect. Having to choose one I choose the Data Flow Diagrams.
Although systems flowcharts provide a useful tool for analyzing a physical description they may impede the design process.
Why is it so valuable?
It is the heart of the system design. It gives the design and flow of data across many systems, databases and sites.
- Identifies the major processes.
- Identifies the major data sources, sinks and stores.
- Identifies the major data flows.
- Names the data flows, processes, sources, sinks and stores.
What information does it contain?
It shows all the pathways and connects to the varies systems, and databases. It would give the overall concept and configurations of the systems. It can also be data flows at varies levels of detail. It can be an overall view, then drilling down to a nuts and bolts view of great detail.
Data flow diagrams assist in building a logical model of the system independent of physical commitments. They show the various flows of data between the processes that transform it. Data stores and the points at which data enters and leaves a system are also shown.
How does it move the Analysis Phase forward?
It provides a place where to start looking first to begin your analysis. It would give you a base line to compare your findings, and prepare a number of questions. It is the base line data design that strip away the hardware layer and focuses more on the logic design and can allow for a clear understanding of the process. It could even make it possible to see new ways to improve the design. It's layering allows for the scaling of ideas, sections and data flows to different degrees of detail.
The data flow design is an important tool of structured analysis and design. It ensures that a top-down approach is taken. This promotes a logical, as opposed to physical, view of data stores, flows and processes.