isn

data types for international product numbering standards

https://www.postgresql.org/docs/current/isn.html

Overview

Package	Version	Category	License	Language
`isn`	`1.2`	TYPE	PostgreSQL	C

ID	Extension	Bin	Lib	Load	Create	Trust	Reloc	Schema
3930	`isn`	No	Yes	No	Yes	Yes	No	-

Related	`prefix` `semver` `unit` `pgpdf` `pglite_fusion` `md5hash` `asn1oid` `roaringbitmap`

Version

PG18	PG17	PG16	PG15	PG14
1.2	1.2	1.2	1.2	1.2

Install

Note: This is a built-in contrib extension of PostgreSQL

CREATE EXTENSION isn;

Usage

isn: ISBN, ISSN, EAN, UPC product number types

The isn extension provides data types for international product numbering standards with validation and check-digit verification.

CREATE EXTENSION isn;

Data Types

Type	Description
`EAN13`	European Article Numbers (always 13-digit)
`ISBN13`	International Standard Book Numbers (13-digit)
`ISMN13`	International Standard Music Numbers (13-digit)
`ISSN13`	International Standard Serial Numbers (13-digit)
`ISBN`	Book numbers (10-digit short format when possible)
`ISMN`	Music numbers (10-digit short format when possible)
`ISSN`	Serial numbers (10-digit short format when possible)
`UPC`	Universal Product Codes

Examples

SELECT isbn('978-0-393-04002-9');
SELECT isbn13('0901690546');
SELECT issn('1436-4522');

-- Create table with ISBN column
CREATE TABLE books (id isbn);
INSERT INTO books VALUES ('9780393040029');

-- Auto-calculate check digit with ?
INSERT INTO books VALUES ('220500896?');

-- Type casting
SELECT ean13('0901690546'::isbn);

Weak Mode

Enable weak mode to accept invalid check digits (useful for OCR/data cleanup):

SET isn.weak TO true;
INSERT INTO books VALUES ('978-0-11-000533-4');
SET isn.weak TO false;

-- Find invalid entries
SELECT id FROM books WHERE NOT is_valid(id);

-- Fix invalid entries
UPDATE books SET id = make_valid(id) WHERE id = '2-205-00876-X!';

Functions

Function	Description
`is_valid(isn)`	Check if value has valid check digit
`make_valid(isn)`	Clear the invalid-check-digit flag
`isn_weak()`	Return current weak mode status
`isn_weak(boolean)`	Set weak mode

Operators and Indexing

Standard comparison operators (=, <, >, <=, >=, <>) with B-tree and hash index support.

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Last Modified 2026-03-12: add pg extension catalog (95749bf)