Main Description |
A business rule defines a specific constraint or invariant that must be satisfied by the business. Business rules may
apply always (in which case they are called invariants) or only under a specific condition. If the condition occurs,
the rule becomes valid, and must therefore be complied with.
Note that a business rule is declarative, not procedural. It describes a desirable, possible state that is suggested,
required or prohibited. It may be conditional, that is, if something is the case, something else must or must not be
the case. It does not, however, describe the steps to be taken to achieve the transition from one state to another, or
the steps to be taken to prohibit a transition. [BRG 2000 - Business Rule Group "Defining Business Rules ~ What Are
They Really?" Revision 1.3 July 2000]
A business rule may provide a set of conditions that govern business behavior or provide the criteria for when an
action is successfully or unsuccessfully completed. It may stipulate what other actions can or cannot be performed as a
result of successful or unsuccessful completion. It may specify the response to some external event that impinges on
the enterprise. It may govern relationships that need to apply among various business entities.
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