Indicator variables can be used with main variables intended for I/O, although certain indicator variables cannot be used for input.
For more information on indicator variables, see Teradata Vantage™ - SQL Stored Procedures and Embedded SQL, B035-1148.
PP2 uses indicator variables to handle nulls sent to or returned from the database, as well as for truncation of a character or byte string when placed into the corresponding main variable.