Micro Focus Visual COBOL 2.3 for Eclipse (Windows) > Programming > Data Access > Database Connectors > Database Connectors Reference > XFD Directives > NULL XFD Directive

NULL XFD Directive

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

The NULL XFD directive handles NULL values in numeric tables by comparing non-key field values when performing read and write actions on the database to determine and perform appropriate actions.

Syntax

$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:

LOW-VALUES
HIGH-VALUES
SPACES
ZEROES

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

During a write to the database, this directive compares the value of the COBOL numeric 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 its own set literal value into the COBOL numeric 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.