From 583905269378bf41c24585773885b1e226a998ce Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter_e@gmx.net>
Date: Thu, 31 Jan 2013 22:31:58 -0500
Subject: Add CREATE RECURSIVE VIEW syntax

This is specified in the SQL standard.  The CREATE RECURSIVE VIEW
specification is transformed into a normal CREATE VIEW statement with a
WITH RECURSIVE clause.

reviewed by Abhijit Menon-Sen and Stephen Frost
---
 doc/src/sgml/ref/create_view.sgml | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

(limited to 'doc/src')

diff --git a/doc/src/sgml/ref/create_view.sgml b/doc/src/sgml/ref/create_view.sgml
index abbde94772c..0745e3cdb59 100644
--- a/doc/src/sgml/ref/create_view.sgml
+++ b/doc/src/sgml/ref/create_view.sgml
@@ -21,7 +21,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ OR REPLACE ] [ TEMP | TEMPORARY ] VIEW <replaceable class="PARAMETER">name</replaceable> [ ( <replaceable class="PARAMETER">column_name</replaceable> [, ...] ) ]
+CREATE [ OR REPLACE ] [ TEMP | TEMPORARY ] [ RECURSIVE ] VIEW <replaceable class="PARAMETER">name</replaceable> [ ( <replaceable class="PARAMETER">column_name</replaceable> [, ...] ) ]
     [ WITH ( <replaceable class="PARAMETER">view_option_name</replaceable> [= <replaceable class="PARAMETER">view_option_value</replaceable>] [, ... ] ) ]
     AS <replaceable class="PARAMETER">query</replaceable>
 </synopsis>
@@ -80,6 +80,23 @@ CREATE [ OR REPLACE ] [ TEMP | TEMPORARY ] VIEW <replaceable class="PARAMETER">n
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term><literal>RECURSIVE</></term>
+    <listitem>
+     <para>
+      Creates a recursive view.  The syntax
+<synopsis>
+CREATE RECURSIVE VIEW <replaceable>name</> (<replaceable>columns</>) AS SELECT <replaceable>...</>;
+</synopsis>
+      is equivalent to
+<synopsis>
+CREATE VIEW <replaceable>name</> AS WITH RECURSIVE <replaceable>name</> (<replaceable>columns</>) AS (SELECT <replaceable>...</>) SELECT <replaceable>columns</> FROM <replaceable>name</>;
+</synopsis>
+      A view column list must be specified for a recursive view.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><replaceable class="parameter">name</replaceable></term>
     <listitem>
@@ -282,6 +299,16 @@ CREATE VIEW comedies AS
    <literal>*</> was used to create the view, columns added later to
    the table will not be part of the view.
   </para>
+
+  <para>
+   Create a recursive view consisting of the numbers from 1 to 100:
+<programlisting>
+CREATE RECURSIVE VIEW nums_1_100 (n) AS
+    VALUES (1)
+UNION ALL
+    SELECT n+1 FROM nums_1_100 WHERE n < 100;
+</programlisting>
+  </para>
  </refsect1>
 
  <refsect1>
-- 
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