vsql_luhn extension for MySQL - VillageSQL Server for MySQL - Documentation

Card numbers, IMEI codes, barcodes, and Canadian social insurance numbers all carry a Luhn check digit, and a wrong digit is the most common way a typed identifier goes bad. vsql_luhn checks that digit and generates it, so a CHECK constraint can refuse a bad number before it reaches a row.


Maintainer	Anurag Ojha
Source and documentation	intojhanurag/vsql-luhn
License	GPL-2.0

A third party writes and maintains this extension. VillageSQL does not build, test, or ship it, and the description below follows the maintainer’s own documentation. Read that documentation before you rely on it.

Install

Build it from the repository, then install it into the server:

INSTALL EXTENSION vsql_luhn;

What it adds

Function	Returns	What it does
`luhn_valid(value)`	int	1 when the string passes the checksum, 0 when it does not. Whitespace and hyphens are ignored, and non-numeric text returns 0 rather than an error
`luhn_checkdigit(partial)`	text	Appends the correct check digit to a partial identifier

Because luhn_valid answers 0 instead of failing on text that is not a number, it drops straight into a WHERE clause over a column of unvalidated input.

See also

Available extensions — the full catalog
intojhanurag/vsql-luhn — source, examples, and the known limitations

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