Configuring precedence rules

A precedence rule suppresses refinements of an Endeca attribute until a condition is met. Suppressing these refinements simplifies navigation through the data and helps avoid information overload problems.

A precedence rule delays the display of standard or managed attributes. In other words, the attribute is hidden until a change in condition triggers its display. As a result, it is easier to navigate through the data and users avoid information overload.

For example, a set of records includes City and State attributes. The application is easier to use if the City attribute is hidden until the user has specified a State. Otherwise, multiple Cities with the same name would be presented, and the user would have difficulty selecting the correct one. For example, choosing "Portland" would return records for both Portland, Maine, and Portland, Oregon. To suppress Cities until a State is selected, create a precedence rule with State as the trigger and City as the target.

You can load precedence rules before loading the standard and managed attributes. The attributes specified in a precedence rule do not have to exist in the data domain when you configure the precedence rule. The Endeca Server does not perform any error checking to ensure that the attributes exist. For this reason, you must ensure that attribute names are spelled correctly in the precedence rule input file.

Moreover, if the trigger attribute specified in a precedence rule does not exist in the data domain, but the target attribute does exist, the precedence rule will never be triggered. This behavior effectively hides the target attribute from refinements. To correct this behavior, either remove the rule or create the trigger attribute in the data domain.