Design

3. Design
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Having understood the user requirements, the systems analyst has to chalk out a blueprint of the proposed system. This is a Herculean task where she has to keep track of inputs, outputs, data storage, processing steps, etc. so that all these components of the system work in harmony giving out the expected results.

The requirements grabbed in the earlier phase of SDLC are now to be mapped onto the computer realm. So the designers try to track back in a logical way from outputs towards inputs, trying to figure out the origin of each of the tidbits appearing in the output and related processing it has to undergo. Each fact/figure in the output has to be either input by the user or processed by the system based on some other user inputs. This processing may bank upon some reference data stored on computers. For example, in a payroll system, the pay slip for each employee is one of the outputs containing all pay details for that employee. Each of those pay details must have been either directly input or computed by the system.

All this presupposes a neat design of the system in terms of inputs, outputs, data storage, codification scheme and data processing.