When an externally described input-only file contains null-capable fields
and the ALWNULL(*INPUTONLY) keyword is specified on a control specification,
the following conditions apply:
When a record is retrieved from a database file and there are some fields
containing null values in the record, database default values for the null-capable
fields will be placed into those fields containing null values. The default
value will be the user defined DDS defaults or system defaults.
You will not be able to determine whether any given field in the record
has a null value.
Control-level indicators, match-field entries and field indicators are
not allowed on an input specification if the input field is a null-capable
field from an externally described input-only file.
Keyed operations are not allowed when factor 1 of a keyed input calculation
operation corresponds to a null-capable key field in an externally described
input-only file.
Note:
The same conditions apply for *INPUTONLY or *YES when specified
on the ALWNULL command parameter.