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Add documentation for the recent 'ALSO' patch for CREATE RULE. Along

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the way, fix a typo and make a few SGML cleanups.
This commit is contained in:
Neil Conway 2004-03-09 19:30:21 +00:00
parent f31a43f9ae
commit 47110ace3a
1 changed files with 40 additions and 24 deletions
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doc/src/sgml/ref/create_rule.sgml
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@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/create_rule.sgml,v 1.43 2004/03/04 14:32:12 momjian Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/create_rule.sgml,v 1.44 2004/03/09 19:30:21 neilc Exp $
PostgreSQL documentation
-->
@ -22,7 +22,7 @@ PostgreSQL documentation
<synopsis>
CREATE [ OR REPLACE ] RULE <replaceable class="parameter">name</replaceable> AS ON <replaceable class="parameter">event</replaceable>
TO <replaceable class="parameter">table</replaceable> [ WHERE <replaceable class="parameter">condition</replaceable> ]
DO [ INSTEAD ] { NOTHING | <replaceable class="parameter">command</replaceable> | ( <replaceable class="parameter">command</replaceable> ; <replaceable class="parameter">command</replaceable> ... ) }
DO [ ALSO | INSTEAD ] { NOTHING | <replaceable class="parameter">command</replaceable> | ( <replaceable class="parameter">command</replaceable> ; <replaceable class="parameter">command</replaceable> ... ) }
</synopsis>
</refsynopsisdiv>
@ -111,7 +111,7 @@ CREATE [ OR REPLACE ] RULE <replaceable class="parameter">name</replaceable> AS
<term><replaceable class="parameter">event</replaceable></term>
<listitem>
<para>
The even is one of <literal>SELECT</literal>,
The event is one of <literal>SELECT</literal>,
<literal>INSERT</literal>, <literal>UPDATE</literal>, or
<literal>DELETE</literal>.
</para>
@ -132,10 +132,10 @@ CREATE [ OR REPLACE ] RULE <replaceable class="parameter">name</replaceable> AS
<term><replaceable class="parameter">condition</replaceable></term>
<listitem>
<para>
Any SQL conditional expression (returning <type>boolean</type>).
The condition expression may not refer to any tables except
<literal>NEW</literal> and <literal>OLD</literal>, and may not
contain aggregate functions.
Any <acronym>SQL</acronym> conditional expression (returning
<type>boolean</type>). The condition expression may not refer
to any tables except <literal>NEW</> and <literal>OLD</>, and
may not contain aggregate functions.
</para>
</listitem>
</varlistentry>
@ -145,8 +145,24 @@ CREATE [ OR REPLACE ] RULE <replaceable class="parameter">name</replaceable> AS
<listitem>
<para>
<literal>INSTEAD</literal> indicates that the commands should be
executed <emphasis>instead</> of the original command, not in
addition to the original command.
executed <emphasis>instead of</> the original command.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>ALSO</option></term>
<listitem>
<para>
<literal>ALSO</literal> indicates that the commands should be
executed <emphasis>in addition to</emphasis> the original
command.
</para>
<para>
If neither <literal>ALSO</literal> nor
<literal>INSTEAD</literal> is specified, <literal>ALSO</literal>
is the default.
</para>
</listitem>
</varlistentry>
@ -156,9 +172,9 @@ CREATE [ OR REPLACE ] RULE <replaceable class="parameter">name</replaceable> AS
<listitem>
<para>
The command or commands that make up the rule action. Valid
commands are <literal>SELECT</literal>,
<literal>INSERT</literal>, <literal>UPDATE</literal>,
<literal>DELETE</literal>, or <literal>NOTIFY</literal>.
commands are <command>SELECT</command>,
<command>INSERT</command>, <command>UPDATE</command>,
<command>DELETE</command>, or <command>NOTIFY</command>.
</para>
</listitem>
</varlistentry>
@ -215,14 +231,14 @@ SELECT * FROM t1;
issued even if there are not any rows that the rule should apply
to. For example, in
<programlisting>
CREATE RULE notify_me AS ON UPDATE TO mytable DO NOTIFY mytable;
CREATE RULE notify_me AS ON UPDATE TO mytable DO ALSO NOTIFY mytable;
UPDATE mytable SET name = 'foo' WHERE id = 42;
</programlisting>
one <command>NOTIFY</command> event will be sent during the
<command>UPDATE</command>, whether or not there are any rows with
<literal>id = 42</literal>. This is an implementation restriction
that may be fixed in future releases.
<command>UPDATE</command>, whether or not there are any rows that
match the condition <literal>id = 42</literal>. This is an
implementation restriction that may be fixed in future releases.
</para>
</refsect1>
@ -232,7 +248,7 @@ UPDATE mytable SET name = 'foo' WHERE id = 42;
<para>
<command>CREATE RULE</command> is a
<productname>PostgreSQL</productname> language extension, as is the
entire rules system.
entire query rewrite system.
</para>
</refsect1>
</refentry>