One of the most common mistakes made by new analysts is confusing functional and nonfunctional requirements. To clarify, functional requirements describe what a system should do, while nonfunctional requirements describe how it should perform.
For example, consider the following list of requirements for a sales system:
- The system should be accessible to web users
- The company standard logo and color scheme should be included
- Access to profitability information should be restricted
- Actual and budgeted cost information should be included
- Management reports should be provided
- Sales information that is updated at least daily should be included
Note that all of these requirements are functional in nature – they describe what the system needs to do. Nonfunctional requirements might include things like response time, scalability, or security measures.
There are several functional business requirements that need to be met:
- A two-second maximum response time for predefined queries
- A ten-minute maximum response time for ad hoc queries
- Include information from all company subsidiaries
- Print subsidiary reports in the primary language of the subsidiary
- Provide monthly rankings of salesperson performance.
To answer your questions:
- The two functional business requirements are a two-second maximum response time for predefined queries and a ten-minute maximum response time for ad hoc queries. Two additional examples could be: providing real-time inventory updates and allowing customers to track their orders online.
- The nonfunctional business requirements are not explicitly stated in the text. However, they may include things like system reliability, scalability, and security. Two additional examples could be: ensuring that the system can handle high traffic volumes during peak periods and protecting customer data with encryption technology.
Functional requirements refer to the specific features that a system must have to meet its intended purpose. The following are examples of functional requirements:
- Provide management reports
- Include information from all company subsidiaries
- Print subsidiary reports in the primary language of the subsidiary
- Include actual and budgeted cost information
- Provide monthly rankings of salesperson performance
In addition, two other examples of functional requirements are:
- Data must be approved by a manager before it can be entered into the system.
- Only managers or administrators have the ability to approve data to be entered into the system.
Non-Functional Requirements:
- Accessibility to web users (Performance)
- Inclusion of the company standard logo and color scheme (Information requirement)
- Restriction of access to profitability information (Control and security requirement)
- Inclusion of sales information that is updated at least daily (Information requirement)
- Two-second maximum response time for predefined queries and ten-minute maximum response time for ad hoc queries (Performance requirement).
There are two additional examples of non-functional requirements that should be considered: users must have sufficient network bandwidth to access the system, and the operating system must be compatible with the program.
