Consider the following guidelines when you define basic rule associations:
When you configure a basic rule association for a reference data field or a field that uses a reference data field, the rule displays only the code field of the referenced code value.
When you configure a basic rule association for the Code field, you must consider the following guidelines:
Ensure that the rule output doesn't include leading or trailing spaces. For example, to concatenate two fields that include leading and trailing spaces, configure basic rule associations, such as left trim and right trim, to eliminate these spaces.
Date fields that you might use must be in the YYYY-MM-DD format.
Basic rule associations with external validation functions validate the code values that you add or update through the user interface and REST API.