geopackage-sdk/src/main/java/mil/nga/geopackage/extension/related/RelatedTablesExtension.java
public List<Long> getMappingsForRelated(ExtendedRelation extendedRelation,
                                            long relatedId) {
        return getMappingsForRelated(extendedRelation.getMappingTableName(),
                relatedId);
    }
public List<Long> getMappingsForRelated(ExtendedRelation extendedRelation,
                                            long relatedId) {
        return getMappingsForRelated(extendedRelation.getMappingTableName(),
                relatedId);
    }
Get the base id mappings for the related id

@param extendedRelation extended relation
@param relatedId        related id
@return IDs representing the matching base IDs