Haley's Definitions of Business Rules
The Process View
Haley has an interesting take on the definition of business rule.
Business rule :is a statement that defines or constrains some aspect of the business. A business rule asserts business structure to control or influence the behavior of the business, i.e. a process or procedure.
Business Rules Control Processes
Note that the definition treats procedures as a legitimate expression of knowledge about a business process of some sort. In the field of Business Process Modeling, the sequence of operations in a business processes can become something like a business rule in itself.
It is an import distinction and the correct view, a process-based or rule-based point of view, depends largely on the category and level of interaction of the business rule under consideration.
"Localized" Business Rules
Business rules tend to appear at the enterprise level. Processes tend to use business rules in a 'localized' way, for instance by geographic location or by market segment. A certain set of business rules can play a role in some aspect or 'facet' of a particular business process. They might even be categorized along several dimensions simultaneously, for instance by geographic location and by market segment at the same time.
The demands of large globalized business applications can generate massive numbers of "localized" rules by combinatorial explosion of 'sub-types', sometimes many thousands of individual categories of business rules. In those situations, a bottom-up, process-based approach to business rules analysis can be very effective.