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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>F.19. isn</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="intarray.html" title="F.18. intarray" /><link rel="next" href="lo.html" title="F.20. lo" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">F.19. isn</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="intarray.html" title="F.18. intarray">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="contrib.html" title="Appendix F. Additional Supplied Modules">Up</a></td><th width="60%" align="center">Appendix F. Additional Supplied Modules</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 11.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="lo.html" title="F.20. lo">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="ISN"><div class="titlepage"><div><div><h2 class="title" style="clear: both">F.19. isn</h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="sect2"><a href="isn.html#id-1.11.7.28.4">F.19.1. Data Types</a></span></dt><dt><span class="sect2"><a href="isn.html#id-1.11.7.28.5">F.19.2. Casts</a></span></dt><dt><span class="sect2"><a href="isn.html#id-1.11.7.28.6">F.19.3. Functions and Operators</a></span></dt><dt><span class="sect2"><a href="isn.html#id-1.11.7.28.7">F.19.4. Examples</a></span></dt><dt><span class="sect2"><a href="isn.html#id-1.11.7.28.8">F.19.5. Bibliography</a></span></dt><dt><span class="sect2"><a href="isn.html#id-1.11.7.28.9">F.19.6. Author</a></span></dt></dl></div><a id="id-1.11.7.28.2" class="indexterm"></a><p>
The <code class="filename">isn</code> module provides data types for the following
international product numbering standards: EAN13, UPC, ISBN (books), ISMN
(music), and ISSN (serials). Numbers are validated on input according to a
hard-coded list of prefixes; this list of prefixes is also used to hyphenate
numbers on output. Since new prefixes are assigned from time to time, the
list of prefixes may be out of date. It is hoped that a future version of
this module will obtained the prefix list from one or more tables that
can be easily updated by users as needed; however, at present, the
list can only be updated by modifying the source code and recompiling.
Alternatively, prefix validation and hyphenation support may be
dropped from a future version of this module.
</p><div class="sect2" id="id-1.11.7.28.4"><div class="titlepage"><div><div><h3 class="title">F.19.1. Data Types</h3></div></div></div><p>
<a class="xref" href="isn.html#ISN-DATATYPES" title="Table F.11. isn Data Types">Table F.11</a> shows the data types provided by
the <code class="filename">isn</code> module.
</p><div class="table" id="ISN-DATATYPES"><p class="title"><strong>Table F.11. <code class="filename">isn</code> Data Types</strong></p><div class="table-contents"><table class="table" summary="isn Data Types" border="1"><colgroup><col /><col /></colgroup><thead><tr><th>Data Type</th><th>Description</th></tr></thead><tbody><tr><td><code class="type">EAN13</code></td><td>
European Article Numbers, always displayed in the EAN13 display format
</td></tr><tr><td><code class="type">ISBN13</code></td><td>
International Standard Book Numbers to be displayed in
the new EAN13 display format
</td></tr><tr><td><code class="type">ISMN13</code></td><td>
International Standard Music Numbers to be displayed in
the new EAN13 display format
</td></tr><tr><td><code class="type">ISSN13</code></td><td>
International Standard Serial Numbers to be displayed in the new
EAN13 display format
</td></tr><tr><td><code class="type">ISBN</code></td><td>
International Standard Book Numbers to be displayed in the old
short display format
</td></tr><tr><td><code class="type">ISMN</code></td><td>
International Standard Music Numbers to be displayed in the
old short display format
</td></tr><tr><td><code class="type">ISSN</code></td><td>
International Standard Serial Numbers to be displayed in the
old short display format
</td></tr><tr><td><code class="type">UPC</code></td><td>
Universal Product Codes
</td></tr></tbody></table></div></div><br class="table-break" /><p>
Some notes:
</p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><p>ISBN13, ISMN13, ISSN13 numbers are all EAN13 numbers.</p></li><li class="listitem"><p>EAN13 numbers aren't always ISBN13, ISMN13 or ISSN13 (some
are).</p></li><li class="listitem"><p>Some ISBN13 numbers can be displayed as ISBN.</p></li><li class="listitem"><p>Some ISMN13 numbers can be displayed as ISMN.</p></li><li class="listitem"><p>Some ISSN13 numbers can be displayed as ISSN.</p></li><li class="listitem"><p>UPC numbers are a subset of the EAN13 numbers (they are basically
EAN13 without the first <code class="literal">0</code> digit).</p></li><li class="listitem"><p>All UPC, ISBN, ISMN and ISSN numbers can be represented as EAN13
numbers.</p></li></ol></div><p>
Internally, all these types use the same representation (a 64-bit
integer), and all are interchangeable. Multiple types are provided
to control display formatting and to permit tighter validity checking
of input that is supposed to denote one particular type of number.
</p><p>
The <code class="type">ISBN</code>, <code class="type">ISMN</code>, and <code class="type">ISSN</code> types will display the
short version of the number (ISxN 10) whenever it's possible, and will show
ISxN 13 format for numbers that do not fit in the short version.
The <code class="type">EAN13</code>, <code class="type">ISBN13</code>, <code class="type">ISMN13</code> and
<code class="type">ISSN13</code> types will always display the long version of the ISxN
(EAN13).
</p></div><div class="sect2" id="id-1.11.7.28.5"><div class="titlepage"><div><div><h3 class="title">F.19.2. Casts</h3></div></div></div><p>
The <code class="filename">isn</code> module provides the following pairs of type casts:
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
ISBN13 <=> EAN13
</p></li><li class="listitem"><p>
ISMN13 <=> EAN13
</p></li><li class="listitem"><p>
ISSN13 <=> EAN13
</p></li><li class="listitem"><p>
ISBN <=> EAN13
</p></li><li class="listitem"><p>
ISMN <=> EAN13
</p></li><li class="listitem"><p>
ISSN <=> EAN13
</p></li><li class="listitem"><p>
UPC <=> EAN13
</p></li><li class="listitem"><p>
ISBN <=> ISBN13
</p></li><li class="listitem"><p>
ISMN <=> ISMN13
</p></li><li class="listitem"><p>
ISSN <=> ISSN13
</p></li></ul></div><p>
When casting from <code class="type">EAN13</code> to another type, there is a run-time
check that the value is within the domain of the other type, and an error
is thrown if not. The other casts are simply relabelings that will
always succeed.
</p></div><div class="sect2" id="id-1.11.7.28.6"><div class="titlepage"><div><div><h3 class="title">F.19.3. Functions and Operators</h3></div></div></div><p>
The <code class="filename">isn</code> module provides the standard comparison operators,
plus B-tree and hash indexing support for all these data types. In
addition there are several specialized functions; shown in <a class="xref" href="isn.html#ISN-FUNCTIONS" title="Table F.12. isn Functions">Table F.12</a>.
In this table,
<code class="type">isn</code> means any one of the module's data types.
</p><div class="table" id="ISN-FUNCTIONS"><p class="title"><strong>Table F.12. <code class="filename">isn</code> Functions</strong></p><div class="table-contents"><table class="table" summary="isn Functions" border="1"><colgroup><col /><col /><col /></colgroup><thead><tr><th>Function</th><th>Returns</th><th>Description</th></tr></thead><tbody><tr><td><code class="function">isn_weak(boolean)</code><a id="id-1.11.7.28.6.3.2.2.1.1.2" class="indexterm"></a></td><td><code class="type">boolean</code></td><td>Sets the weak input mode (returns new setting)</td></tr><tr><td><code class="function">isn_weak()</code></td><td><code class="type">boolean</code></td><td>Gets the current status of the weak mode</td></tr><tr><td><code class="function">make_valid(isn)</code><a id="id-1.11.7.28.6.3.2.2.3.1.2" class="indexterm"></a></td><td><code class="type">isn</code></td><td>Validates an invalid number (clears the invalid flag)</td></tr><tr><td><code class="function">is_valid(isn)</code><a id="id-1.11.7.28.6.3.2.2.4.1.2" class="indexterm"></a></td><td><code class="type">boolean</code></td><td>Checks for the presence of the invalid flag</td></tr></tbody></table></div></div><br class="table-break" /><p>
<em class="firstterm">Weak</em> mode is used to be able to insert invalid data
into a table. Invalid means the check digit is wrong, not that there are
missing numbers.
</p><p>
Why would you want to use the weak mode? Well, it could be that
you have a huge collection of ISBN numbers, and that there are so many of
them that for weird reasons some have the wrong check digit (perhaps the
numbers were scanned from a printed list and the OCR got the numbers wrong,
perhaps the numbers were manually captured... who knows). Anyway, the point
is you might want to clean the mess up, but you still want to be able to
have all the numbers in your database and maybe use an external tool to
locate the invalid numbers in the database so you can verify the
information and validate it more easily; so for example you'd want to
select all the invalid numbers in the table.
</p><p>
When you insert invalid numbers in a table using the weak mode, the number
will be inserted with the corrected check digit, but it will be displayed
with an exclamation mark (<code class="literal">!</code>) at the end, for example
<code class="literal">0-11-000322-5!</code>. This invalid marker can be checked with
the <code class="function">is_valid</code> function and cleared with the
<code class="function">make_valid</code> function.
</p><p>
You can also force the insertion of invalid numbers even when not in the
weak mode, by appending the <code class="literal">!</code> character at the end of the
number.
</p><p>
Another special feature is that during input, you can write
<code class="literal">?</code> in place of the check digit, and the correct check digit
will be inserted automatically.
</p></div><div class="sect2" id="id-1.11.7.28.7"><div class="titlepage"><div><div><h3 class="title">F.19.4. Examples</h3></div></div></div><pre class="programlisting">
--Using the types directly:
SELECT isbn('978-0-393-04002-9');
SELECT isbn13('0901690546');
SELECT issn('1436-4522');
--Casting types:
-- note that you can only cast from ean13 to another type when the
-- number would be valid in the realm of the target type;
-- thus, the following will NOT work: select isbn(ean13('0220356483481'));
-- but these will:
SELECT upc(ean13('0220356483481'));
SELECT ean13(upc('220356483481'));
--Create a table with a single column to hold ISBN numbers:
CREATE TABLE test (id isbn);
INSERT INTO test VALUES('9780393040029');
--Automatically calculate check digits (observe the '?'):
INSERT INTO test VALUES('220500896?');
INSERT INTO test VALUES('978055215372?');
SELECT issn('3251231?');
SELECT ismn('979047213542?');
--Using the weak mode:
SELECT isn_weak(true);
INSERT INTO test VALUES('978-0-11-000533-4');
INSERT INTO test VALUES('9780141219307');
INSERT INTO test VALUES('2-205-00876-X');
SELECT isn_weak(false);
SELECT id FROM test WHERE NOT is_valid(id);
UPDATE test SET id = make_valid(id) WHERE id = '2-205-00876-X!';
SELECT * FROM test;
SELECT isbn13(id) FROM test;
</pre></div><div class="sect2" id="id-1.11.7.28.8"><div class="titlepage"><div><div><h3 class="title">F.19.5. Bibliography</h3></div></div></div><p>
The information to implement this module was collected from
several sites, including:
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p><a class="ulink" href="https://www.isbn-international.org/" target="_top">https://www.isbn-international.org/</a></p></li><li class="listitem"><p><a class="ulink" href="http://www.issn.org/" target="_top">http://www.issn.org/</a></p></li><li class="listitem"><p><a class="ulink" href="https://www.ismn-international.org/" target="_top">https://www.ismn-international.org/</a></p></li><li class="listitem"><p><a class="ulink" href="https://www.wikipedia.org/" target="_top">https://www.wikipedia.org/</a></p></li></ul></div><p>
The prefixes used for hyphenation were also compiled from:
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p><a class="ulink" href="https://www.gs1.org/standards/id-keys" target="_top">https://www.gs1.org/standards/id-keys</a></p></li><li class="listitem"><p><a class="ulink" href="https://en.wikipedia.org/wiki/List_of_ISBN_identifier_groups" target="_top">https://en.wikipedia.org/wiki/List_of_ISBN_identifier_groups</a></p></li><li class="listitem"><p><a class="ulink" href="https://www.isbn-international.org/content/isbn-users-manual" target="_top">https://www.isbn-international.org/content/isbn-users-manual</a></p></li><li class="listitem"><p><a class="ulink" href="https://en.wikipedia.org/wiki/International_Standard_Music_Number" target="_top">https://en.wikipedia.org/wiki/International_Standard_Music_Number</a></p></li><li class="listitem"><p><a class="ulink" href="https://www.ismn-international.org/ranges.html" target="_top">https://www.ismn-international.org/ranges.html</a></p></li></ul></div><p>
Care was taken during the creation of the algorithms and they
were meticulously verified against the suggested algorithms
in the official ISBN, ISMN, ISSN User Manuals.
</p></div><div class="sect2" id="id-1.11.7.28.9"><div class="titlepage"><div><div><h3 class="title">F.19.6. Author</h3></div></div></div><p>
Germán Méndez Bravo (Kronuz), 2004 - 2006
</p><p>
This module was inspired by Garrett A. Wollman's
<code class="filename">isbn_issn</code> code.
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