Non-functional requirement

The plan for implementing functional requirements is detailed in the system design.

Functional requirements are usually in the form of "system shall do ", an individual action or part of the system, perhaps explicitly in the sense of a mathematical function, a black box description input, output, process and control functional model or IPO model.

The system's overall properties commonly mark the difference between whether the development project has succeeded or failed.

[7][8] A system may be required to present the user with a display of the number of records in a database.

If the number needs to be updated in real time, the system architects must ensure that the system is capable of displaying the record count within an acceptably short interval of the number of records changing.