This topic guides you when you are setting up field validation for form definitions.
If you fill in the Checksum box in the Field dialog, FORMS performs a modulo 10 check-digit control of a numeric field.
Type Modulo10(i,j,k), where i - j indicate the positions of the digits to base the calculations on and k is the position of the check digit.
Example:
A field contains a number such as 223344-5567, and the last digit, 7, is the check digit. You type Modulo10(1,9,10) because the number to be checked is actually 223344-556 (in positions 1-9) and 7 (in position 10) is the check digit.
If the format is variable, indicate the longest possible format. The check digit position is locked to the end of the format.
The checksum is performed when the field is interpreted, and again if the field value changes during verification.
It is possible to use other check-digit controls (besides Module10) with FORMS. However, implementing them requires customization.