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Add CREATE RECURSIVE VIEW syntax

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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
This commit is contained in:
Peter Eisentraut
2013-01-31 22:31:58 -05:00
parent b1980f6d03
commit 5839052693
4 changed files with 158 additions and 1 deletions
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29
doc/src/sgml/ref/create_view.sgml
View File

@@ -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>