Check Digit Functions

Two SQL functions are used to generate and validate a check digit.

The function GENERATE_DIGIT generates a check digit for a specified string. The check digit can be used to help determine if a string, such as a credit card number, has been entered correctly.

The function VALIDATE_DIGIT tests if the check digit is valid.

Syntax for these functions is:

GENERATE_DIGIT('scheme', 'string')

which returns the check digit as a character.

VALIDATE_DIGIT('scheme', 'string')

which returns 1 for valid, 0 for invalid.

The scheme can be one of the following check digit schemes:

• LUHN or LUHN_A
• VERHOEFF or VERHOEFFNR
• ISBN
• ISBN_13
• ISSN
• UPC, UPC_A, or EAN_12
• UPC_E
• EAN, EAN_13, GTIN_13, or JAN
• EAN_8 or GTIN_8

For details, see the GENERATE_DIGIT and VALIDATE_DIGIT sections under String Functions in the SQL Reference Guide.