Is anyone actually using the Null Indicator support in the database?
In DDS, you need to use ALWNUL keyword.
In SQL it is the default for all fields UNLESS you specify "NOT NULL".
When using RPG native I/O the ALWNULL(*USRCTL) is necessary to acknowledge NULLs in database records, and the %NULLIND(myField) built-in function is used to test and set the null "indicator" for the field.
When using SQL I/O in RPG IV, ALWNULL(*USRCTL) is also necessary, however the null indicator is tested/set using a 5i0 (2-byte signed integer) variable that's returned on a FETCH or set on an UPDATE/INSERT operation.
%NULLIND has nothing to do with anything when SQL is used. So conversion between the two could be necessary.
With %NULLIND the classic *ON or *OFF status can be tested:
With SQL Null Indicators:
See these two related articles for additional information: