private FieldSchema convertOrcTypeToFieldSchema(String fieldName, TypeDescription fieldType) {
    String typeName = convertOrcTypeToFieldType(fieldType);
    return new FieldSchema(fieldName, typeName, "Inferred from Orc file.");
  }
NOTE: if {@link serdeConstants#LIST_COLUMN_TYPES} is missing, all columns will be of String type.
ql/src/java/org/apache/hadoop/hive/ql/io/orc/OrcSerde.java