From 8073fff8e486178a49b64ef81a15a1e51294d7d0 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter_e@gmx.net>
Date: Fri, 20 Apr 2007 21:51:46 +0000
Subject: [PATCH] Documentation for UUID type
---
doc/src/sgml/datatype.sgml | 51 +++++++++++++++++++++++++++++++++++++-
1 file changed, 50 insertions(+), 1 deletion(-)
diff --git a/doc/src/sgml/datatype.sgml b/doc/src/sgml/datatype.sgml
index d58156bd70e..cda0f50d94b 100644
--- a/doc/src/sgml/datatype.sgml
+++ b/doc/src/sgml/datatype.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.196 2007/04/17 17:30:34 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.197 2007/04/20 21:51:46 petere Exp $ -->
<chapter id="datatype">
<title id="datatype-title">Data Types</title>
@@ -234,6 +234,12 @@
<entry>date and time, including time zone</entry>
</row>
+ <row>
+ <entry><type>uuid</type></entry>
+ <entry></entry>
+ <entry>universally unique identifier</entry>
+ </row>
+
<row>
<entry><type>xml</type></entry>
<entry></entry>
@@ -3199,6 +3205,49 @@ SELECT * FROM test;
</para>
</sect1>
+ <sect1 id="datatype-uuid">
+ <title><acronym>UUID</acronym> Type</title>
+
+ <indexterm zone="datatype-xml">
+ <primary>UUID</primary>
+ </indexterm>
+
+ <para>
+ The data type <type>uuid</type> stores Universally Unique
+ Identifiers (UUID) as per RFC 4122, ISO/IEC 9834-8:2005, and
+ related standards. (Some systems refer to this data type as
+ globally unique
+ identifier/GUID<indexterm><primary>GUID</primary></indexterm>
+ instead.) Such an identifier is a 128-bit quantity that is
+ generated by a suitable algorithm so that it is very unlikely to
+ be generated by anyone else in the known universe using the same
+ algorithm. Therefore, for distributed systems, these identifiers
+ provide a better uniqueness guarantee than that which can be
+ achieved using sequence generators, which are only unique within a
+ single database.
+ </para>
+
+ <para>
+ A UUID is written as a sequence of lower-case hexadecimal digits,
+ in several groups separated by hyphens, specifically a group of 8
+ digits followed by three groups of 4 digits followed by a group of
+ 12 digits, for a total of 32 digits representing the 128 bits. An
+ example of a UUID in this standard form is:
+<programlisting>
+a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11
+</programlisting>
+ PostgreSQL also accepts the following alternative forms for input:
+ use of upper-case digits, the standard format surrounded by
+ braces, and omitting the hyphens. Examples are:
+<programlisting>
+A0EEBC99-9C0B-4EF8-BB6D-6BB9BD380A11
+{a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11}
+a0eebc999c0b4ef8bb6d6bb9bd380a11
+</programlisting>
+ Output is always in the standard form.
+ </para>
+ </sect1>
+
<sect1 id="datatype-xml">
<title><acronym>XML</> Type</title>
--
GitLab