About
A business rule is a rule that constrains some aspect of the business process.
According to the white paper by the Business Rules Group, a business rule falls in this category:
- Definitions of business terms (Entity)
The most basic element of a business rule is the language used to express it. The very definition of a term is itself a business rule that describes how people think and talk about things. Thus, defining a term is establishing a category of business rule. Terms have traditionally been documented in a Glossary or as entities
E.g. a customer can place one or many order is a business rule. Facts can be documented as natural language sentences or as relationships, cardinality, attributes
- Constraints (also called “action assertions”)
Every enterprise constrains behaviour in some way, and this is closely related to constraints on what data may or may not be updated. To prevent a record from being made is, in many cases, to prevent an action from taking place.
- Derivations (calculated or deduced)
The business rules can be completely represented in a logical data model
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Example
Example of a business rule for an application that will register submitted papers:
- Each Committee ChairedBy at most one Person
- Each Person who chairs a Committee must also IsMemberOf that Committee
- Each Reviewer Reviews at least one Paper
- Each Paper which is WrittenBy a Person must not ReviewedBy with that Person