From IHRIS Wiki
What is a business rule? It is a simple, declarative statement that describes an operation, definition or constraint that applies to an organization in achieving its goals. A business rule tells the organization what it can do, not how it can do it.
Check all of the following when determining what business rules exist that may affect the system:
- Givens (whether implicit or explicit)
- Marketing strategies (branding and identity)
- Organizational mission, vision, purpose
- Organizational policies and procedures
- Legal requirements
- Political requirements
- Computations and conversions used by the organization
- Workflow requirements (triggers, approvals, review, other internal processes)
- Unwritten practices (generally discovered through interviewing)
If you have only a handful of business rules, you may choose to document them right in the use cases. A rule of thumb: start out including them in the use cases until it becomes obvious, or painful, to do so. This may be because the sheer number of business rules is dominating the use case or because the same business rule is referenced in two or more use cases.
For complex systems that heavily rely on understanding business rules to function correctly, consider using the following template to capture the business rules. The template may be modified to suit development needs.
Business Rule Name
Description: Detailed description of the rule. Typically written in structured English or pseudo code. Consider using a flowchart or UML activity diagram to depict procedural logic.
Example: Optional section. Sometimes a business rule is easier to understand when one or more examples are provided.
Related Rules: Optional section. List other business rules related to this one.
Reference(s): Applicable references, such as explanatory documents (printed or electronic), pertinent to this business rule.
Assumptions: List assumptions made. Indicate "none" if none.
Notes: Optional section. List any "to dos", concerns to be addressed, etc. List any important decisions made during the development of this business rule.