Precedence rules and implicit attribute value selection

When all records in the navigation state are assigned a given attribute value, that attribute value is an implicit selection.

In addition to being selected explicitly by the application, attribute values (either standard attribute values or managed attribute values) can be selected implicitly. For example, if all Champagnes are from France, then the explicit selection of WineType > Champagne causes the implicit selection of Region > France. Implicit selection is a function of the set of records in the navigation state, regardless of what combination of search, navigation, and record filters was used to obtain them.

Implicitly-selected attribute values trigger precedence rules in exactly the same way as explicitly-selected attribute values. This behavior helps ensure a consistent user experience, by providing the same attributes for refinement of a given result set, regardless of whether that result set was obtained through search, navigation, or a combination of the two.

For this reason, two navigation paths leading to the same set of records will always have exactly the same set of navigation selections (differing only in whether the selections are implicit or explicit). Because of this equivalence, the set of precedence rules fired in both states will be identical.

When precedence rules are overridden

Implicit selection of a precedence rule's trigger attribute value fires the rule. Under some circumstances, implicit selection of the rule's target managed value also fires it. Specifically, when a precedence rule's target managed value is implicit in the navigation state, and when refinements are available underneath that target managed value, the precedence rule fires and the target attribute is displayed. This occurs even when none of the rule's trigger values have been implicitly or explicitly selected. The Oracle Endeca Server treats any precedence rules targeting the parent managed attributes of these managed values as having fired, even though the rules' trigger values have not been selected.

For this reason, precedence rule target attributes may appear when no precedence rule trigger has been selected.