I believe you have gone through my previous article on the requirement. If not I would recommend going through it once as Requirement is the very first stage of Software Development Life Cycle and designing come after that,
What is Designing?
After analyzing the complete requirement now, it’s time to design the system. Complete analysis and understanding of the requirement is the entry point of the system design phase. Based on the requirement and its analysis new system will take start taking shape from this phase. In requirement analysis, we develop the logical system and in this phase that logical system starts taking shape in a physical system. In this phase we try to draw input/ output, schema, database, data flow, etc.. In the same phase we decide for the programming language and software required for the system development and hardware may require during the development process.
Designing is usually done using the standard way of doing it like DFD, Flowchart, Decision table, decision tree. In future, I will try to write some explanatory blog post on the about process of Designing.
This is the phase where we make a decision about the system of how the system will meet the requirement defined in the requirement analysis phase. In another word, we can say that it is the phase where we design high-level specification. Later this stage this high-level specification will convert in the system.
After understanding requirement in a good way, here we decide the different elements of the system, different components, system architecture, different modules, different interfaces and sometimes test data would be defined which will pass through the system.
In practical life, the team start scratching the paper with a pen and try to determine how the system will function and how it will look. From these papers, we start developing the system which will satisfy the requirement logically and physically.