The ImportDefinitionFieldMappingType object defines how fields in an import file are mapped to fields in a data extension.

NameData TypeDescription
InferFromColumnHeadingsEnumerationIndicates system matches field headings in import file to data extension fields as accurately as possible based on similarities in text and values.
ManualMapEnumerationIndicates that all relationships between fields in an import file and a data extension are explicitly stated in the API call.
MapByOrdinalEnumerationIndicates fields are mapped from an import field to a data extension by their ordinal position in the file. Use a 0-based ordinal when importing to a subscriber list, and use a 1-based ordinal when importing to a data extension.