Why would you set Choice Action to Ignore on a transform field map?

The Choice Action setting on a transform field map determines how the system handles an incoming value for a choice or reference field when that value does not match an existing choice or referenced record. Setting this action to Ignore instructs the import process to skip the transformation for that specific field, leaving it blank on the target record, but continuing to process the rest of the row. This is the correct strategy when you want to prevent the automatic creation of new, potentially invalid, choices or referenced records (i.e., "dummy records") in the target tables, thereby maintaining data integrity.

B. To reject new rows that doen't have choice values present. This describes the reject choice action, which stops the transformation for the entire row if a matching choice or reference value is not found.
C. To insert missing rows in a referenced table. This describes the create choice action, which automatically creates a new choice or a new record in the referenced table if a match is not found.
D. To transform a field value using a script. Transforming a field value with a script is accomplished by enabling the Use source script option in the field map, not by setting the Choice Action.

1. ServiceNow Product Documentation - Field maps: In the section "Create new choices or add new referenced records," the documentation outlines the three Choice action options. It specifies that ignore will "ignore new values in the source field," which directly supports the reasoning for avoiding the creation of new records.

2. ServiceNow Product Documentation - Add a field map: This document details the fields on the Field Map form. For the Choice action field, it states that ignore will "ignore the new value." This confirms that the field's value is disregarded, preventing the creation of a new record as described in the create option.