NULL XFD Directive

Restriction: This topic applies only when a Database Connectors license has been installed via the Micro Focus License Management System.

The NULL XFD directive allows the specification of a value which would indicate a field's contents are to be treated as NULL in interactions with the DBMS. It enables Database Connectors to handle NULL values by comparing values when performing read and write actions on the database to determine and perform appropriate actions. This directive is only valid with non-key fields.


$XFD NULL=literal
where literal is any literal value, or one of the following special literals to indicate that the field is comprised entirely of a specific type of value:

Specify the NULL XFD directive on individual fields within the COBOL FD.

During a write to the database, this directive compares the value of the COBOL field against its own set literal value. If the values are equal, it writes a NULL value to the database.

During a read of the database, if a NULL value is returned, this directive places the specified literal value into the COBOL field before returning to the COBOL program.

Note: Fields allowing NULL values are not allowed as part of a record key. If the compiler encounters a record key containing NULL values, it returns a syntax error.