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diff --git a/doc/src/sgml/html/plperl-triggers.html b/doc/src/sgml/html/plperl-triggers.html new file mode 100644 index 0000000..3043a8f --- /dev/null +++ b/doc/src/sgml/html/plperl-triggers.html @@ -0,0 +1,74 @@ +<?xml version="1.0" encoding="UTF-8" standalone="no"?> +<!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>45.6. PL/Perl Triggers</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="plperl-trusted.html" title="45.5. Trusted and Untrusted PL/Perl" /><link rel="next" href="plperl-event-triggers.html" title="45.7. PL/Perl Event Triggers" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">45.6. PL/Perl Triggers</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="plperl-trusted.html" title="45.5. Trusted and Untrusted PL/Perl">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="plperl.html" title="Chapter 45. PL/Perl — Perl Procedural Language">Up</a></td><th width="60%" align="center">Chapter 45. PL/Perl — Perl Procedural Language</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 15.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="plperl-event-triggers.html" title="45.7. PL/Perl Event Triggers">Next</a></td></tr></table><hr /></div><div class="sect1" id="PLPERL-TRIGGERS"><div class="titlepage"><div><div><h2 class="title" style="clear: both">45.6. PL/Perl Triggers</h2></div></div></div><p> + PL/Perl can be used to write trigger functions. In a trigger function, + the hash reference <code class="varname">$_TD</code> contains information about the + current trigger event. <code class="varname">$_TD</code> is a global variable, + which gets a separate local value for each invocation of the trigger. + The fields of the <code class="varname">$_TD</code> hash reference are: + + </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">$_TD->{new}{foo}</code></span></dt><dd><p> + <code class="literal">NEW</code> value of column <code class="literal">foo</code> + </p></dd><dt><span class="term"><code class="literal">$_TD->{old}{foo}</code></span></dt><dd><p> + <code class="literal">OLD</code> value of column <code class="literal">foo</code> + </p></dd><dt><span class="term"><code class="literal">$_TD->{name}</code></span></dt><dd><p> + Name of the trigger being called + </p></dd><dt><span class="term"><code class="literal">$_TD->{event}</code></span></dt><dd><p> + Trigger event: <code class="literal">INSERT</code>, <code class="literal">UPDATE</code>, + <code class="literal">DELETE</code>, <code class="literal">TRUNCATE</code>, or <code class="literal">UNKNOWN</code> + </p></dd><dt><span class="term"><code class="literal">$_TD->{when}</code></span></dt><dd><p> + When the trigger was called: <code class="literal">BEFORE</code>, + <code class="literal">AFTER</code>, <code class="literal">INSTEAD OF</code>, or + <code class="literal">UNKNOWN</code> + </p></dd><dt><span class="term"><code class="literal">$_TD->{level}</code></span></dt><dd><p> + The trigger level: <code class="literal">ROW</code>, <code class="literal">STATEMENT</code>, or <code class="literal">UNKNOWN</code> + </p></dd><dt><span class="term"><code class="literal">$_TD->{relid}</code></span></dt><dd><p> + OID of the table on which the trigger fired + </p></dd><dt><span class="term"><code class="literal">$_TD->{table_name}</code></span></dt><dd><p> + Name of the table on which the trigger fired + </p></dd><dt><span class="term"><code class="literal">$_TD->{relname}</code></span></dt><dd><p> + Name of the table on which the trigger fired. This has been deprecated, + and could be removed in a future release. + Please use $_TD->{table_name} instead. + </p></dd><dt><span class="term"><code class="literal">$_TD->{table_schema}</code></span></dt><dd><p> + Name of the schema in which the table on which the trigger fired, is + </p></dd><dt><span class="term"><code class="literal">$_TD->{argc}</code></span></dt><dd><p> + Number of arguments of the trigger function + </p></dd><dt><span class="term"><code class="literal">@{$_TD->{args}}</code></span></dt><dd><p> + Arguments of the trigger function. Does not exist if <code class="literal">$_TD->{argc}</code> is 0. + </p></dd></dl></div><p> + </p><p> + Row-level triggers can return one of the following: + + </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">return;</code></span></dt><dd><p> + Execute the operation + </p></dd><dt><span class="term"><code class="literal">"SKIP"</code></span></dt><dd><p> + Don't execute the operation + </p></dd><dt><span class="term"><code class="literal">"MODIFY"</code></span></dt><dd><p> + Indicates that the <code class="literal">NEW</code> row was modified by + the trigger function + </p></dd></dl></div><p> + </p><p> + Here is an example of a trigger function, illustrating some of the + above: +</p><pre class="programlisting"> +CREATE TABLE test ( + i int, + v varchar +); + +CREATE OR REPLACE FUNCTION valid_id() RETURNS trigger AS $$ + if (($_TD->{new}{i} >= 100) || ($_TD->{new}{i} <= 0)) { + return "SKIP"; # skip INSERT/UPDATE command + } elsif ($_TD->{new}{v} ne "immortal") { + $_TD->{new}{v} .= "(modified by trigger)"; + return "MODIFY"; # modify row and execute INSERT/UPDATE command + } else { + return; # execute INSERT/UPDATE command + } +$$ LANGUAGE plperl; + +CREATE TRIGGER test_valid_id_trig + BEFORE INSERT OR UPDATE ON test + FOR EACH ROW EXECUTE FUNCTION valid_id(); +</pre><p> + </p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="plperl-trusted.html" title="45.5. Trusted and Untrusted PL/Perl">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="plperl.html" title="Chapter 45. PL/Perl — Perl Procedural Language">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="plperl-event-triggers.html" title="45.7. PL/Perl Event Triggers">Next</a></td></tr><tr><td width="40%" align="left" valign="top">45.5. Trusted and Untrusted PL/Perl </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 15.5 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 45.7. PL/Perl Event Triggers</td></tr></table></div></body></html>
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