Software Engineering-software requirements

Software requirements include three different layers

Business Requirements, user requirements, and functional requirements. In addition, each system has various non-functional requirements.

Business Requirement indicates a high-level goal of an organization or a customer. Business needs usually come from project investors, customers who purchase products, managers of actual users, marketing departments, or product planning departments.

Business Requirements describe why an organization wants to develop a system, that is, what the organization wants to achieve.Use the vision and scope document to record business needs, which is also called a project profile or market demand document.

User requirement describes the user's target or the task that the system must complete.Use Cases, scenario descriptions, and events-response tables are all effective ways to express user needs. That is to say, the user requirement describes what the user can do with the system.

Functional requirements (functional requirement) specifies the software functions that developers must implement in the product. Users can use these functions to complete tasks and meet business needs. Functional requirements are sometimes referred to as behavior requirements, because they are always described as "should: "The system should send an email to notify users that they have accepted their reservation ".Description of functional requirements is what developers need to implement.

System requirements are used to describe the top-level requirements of products (that is, systems) that contain multiple subsystems. The system can contain only the software system or both the software and hardware subsystem.

Software Engineering-software requirements