Acu4GL allows you to work with dates in a Julian format by specifying a mask to fields with the date directive. Most integers are considered to be valid for Julian dates. This makes it impossible for your application to be able to write "NULL" to a database column that is of type date if you are using a Julian mask.
If you wish to be able to write "NULL" to a database date field that is described in your COBOL program with a Julian date mask, use 4GL-JULIAN-NULL. This configuration variable specifies the value of the COBOL data item that should be considered as "NULL". When Acu4GL is writing data to a date field and the value of the COBOL data item is equal to the value of this variable, "NULL" will be written to the database column. If Acu4GL is reading a date column, and the value of that column is "NULL", the value of this configuration variable will be returned to your COBOL program.