DB/Assist only allows columns defined in DB/2 as "nullable", to be assigned a null indicator variable. If you have manually created an OUTER joint statement, it is possible that certain columns will be returned as nulls. To distinguish between an apparent null return, for example a blank string, and null column, you will need to manually alter the action routine generated by DB/Assist. Each host variable used within each SQL statement will be "bound" to an ESL variable using the EDB2SetVariable function. When no null indicator is specified, the default variable "EDB2NULL_IV" is used. You should replace the "EDB2NULL_IV" variable, with a different integer variable, which you can test with an "if" statement after the row has been fetched. When the column in the fetched row is null, then the associated integer variable will equal 1 (one).

As DB/Assist overwrites the action routines held with the ".ACT" files each time the SQL Access Module is compiled, you must re-apply the above amendment each time a compile is performed, prior to compiling the ESL Applications that include the action routines.