essence of business rules

Business rules may be categorised into:

• information validation rules
• information derivation rules
• decision rules

The rules for all of these categorisations will identify the information types for which values are required.

Within the context of a rule based information system, there is little difference between "information derivation rules" and "decision rules".

A decision will be defined by:

• derived values that may drive a software process
• the issue of a directive internally or externally to the system
• the definition, in an interactive system of the next piece of information required

Each rule based process will require a definitive set of rules. Where the same process is repeated in different systems, the same set of rules will be applied, reducing duplication and the potential for inconsistency.

The application software:

• defines the required rule set
• makes the relevant input data available
• invokes the rule engine

The rule engine:

• applies the rules to validate the input data
• applies the rules to derive new information
• applies the rules to make any decisions
• makes the relevant data available
• returns control to the application software