I hope to put the concept of business rule extraction and reuse into a context that organizations can readily begin to deploy. In order to define legacy business rule extraction, we must first define a legacy system. A legacy system is any technology that has evolved over the past 50 years and is currently managing information in a production environment. This begs another question. Rules are declarations of policy or conditions that must be satisfied.
Business rules are rules that govern the way a business operates.
For purpose of legacy business rule extraction, we narrowed the OMG definitions to the following. A business rule is a combination of conditional and imperative logic that changes the state of an object or data element. An example might help clarify this definition. Business rule extraction identifies and captures any combination of conditional and imperative statements and isolates these statements to facilitate the understanding and reuse of knowledge contained within legacy information systems. Rules can invoke other rules and be represented within a rule hierarchy.