About precedence rules

A precedence rule allows your application to suppress refinements for an Endeca attribute until some condition is met. This makes navigation through the data easier and is essential to avoid information overload problems.

Precedence rules allow your application to delay the display of Endeca standard or managed attributes the user triggers the display. In other words, precedence rules are triggers that cause attributes that were not previously displayed to now be available. This makes navigation through the data easier, and is essential to avoid information overload problems.

For example, suppose the records in an application have separate City and State attributes. It would make sense to hide the City attribute until the user has narrowed down to a specific State, because it doesn't make sense to pick a City before a State. (For example, choosing "Portland" would select records in both Portland, OR and Portland, ME.) To accomplish this, create a precedence rule with State as the trigger and City as the target.

The standard and/or managed attributes referenced in precedence rules do not have to exist in the MDEX Engine at ingest time. That is, no error checking is done for the existence of the attributes (this allows the rules to be created even before the data they reference is loaded). For this reason, you must make sure that the attributes are spelled correctly in the input file.

Note that if the trigger attribute in a precedence rule does not exist in the MDEX Engine but its target attribute does exist, then 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 MDEX Engine.