Forward chaining : Forward chaining is an internal mechanism that allows changes in one property value to be automatically propagated to other property values or indexes. For example, if the area property is dependent on the length and width properties, forward Chaining will cause the area property to be recalculated if the length or width values change.
Backward Chaining : Backward chaining allows for automatic property calculation by executing the declarative rule when the value for the property is required rather than when the input changes. If the area property is dependent on the length and width properties, for example, backward chaining forces the area property to be computed each time it is needed. Except for the Rule-Declare-Expression, almost all declarative rules only implement forward chaining. We have the option of going forward or backward chaining in rule-Declare-Expression.
