Pathmaker Programming Guide

Using Null Values
Defining Data for a NonStop SQL Pathmaker Application
067868 Tandem Computers Incorporated C–3
For items declared as alphanumeric, the data type remains the same. For
example:
CREATE TABLE employee (name PIC X(20));
would be generated in COBOL as:
01 EMPLOYEE.
02 NAME.
03 INDICATOR PIC S9(4) COMP VALUE 0.
03 VALU PIC X(20)
VALUE SPACE.
You would not get a compiler error, but your program would not perform
correctly if you tried to move an alphanumeric value to NAME OF EMPLOYEE.
To move a value in the Custom Source File of a service to a host variable that
allows null values, you must code the move to refer to the elementary item VALU
rather than to the group level item. To move a value to NAME OF EMPLOYEE in
the Custom Source File, you would write a statement that looks something like
this:
MOVE "SMITH" TO VALU OF NAME OF EMPLOYEE.
Note If you drop a table and re-create it so that columns in the table allow null values, you should rewrite and
recompile any existing code that moves values to the altered columns.
The INDICATOR field will never show up in the Display Field List and the value
of the INDICATOR will never appear on the screen in the target application.
Other considerations for using null values differ depending on whether you are using
database (DB) requesters or transaction (TRNS) requesters.