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diff --git a/doc/src/sgml/html/functions-event-triggers.html b/doc/src/sgml/html/functions-event-triggers.html new file mode 100644 index 0000000..e127443 --- /dev/null +++ b/doc/src/sgml/html/functions-event-triggers.html @@ -0,0 +1,133 @@ +<?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>9.29. Event Trigger Functions</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="functions-trigger.html" title="9.28. Trigger Functions" /><link rel="next" href="functions-statistics.html" title="9.30. Statistics Information Functions" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">9.29. Event Trigger Functions</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="functions-trigger.html" title="9.28. Trigger Functions">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="functions.html" title="Chapter 9. Functions and Operators">Up</a></td><th width="60%" align="center">Chapter 9. Functions and Operators</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 16.2 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="functions-statistics.html" title="9.30. Statistics Information Functions">Next</a></td></tr></table><hr /></div><div class="sect1" id="FUNCTIONS-EVENT-TRIGGERS"><div class="titlepage"><div><div><h2 class="title" style="clear: both">9.29. Event Trigger Functions <a href="#FUNCTIONS-EVENT-TRIGGERS" class="id_link">#</a></h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="sect2"><a href="functions-event-triggers.html#PG-EVENT-TRIGGER-DDL-COMMAND-END-FUNCTIONS">9.29.1. Capturing Changes at Command End</a></span></dt><dt><span class="sect2"><a href="functions-event-triggers.html#PG-EVENT-TRIGGER-SQL-DROP-FUNCTIONS">9.29.2. Processing Objects Dropped by a DDL Command</a></span></dt><dt><span class="sect2"><a href="functions-event-triggers.html#PG-EVENT-TRIGGER-TABLE-REWRITE-FUNCTIONS">9.29.3. Handling a Table Rewrite Event</a></span></dt></dl></div><p> + <span class="productname">PostgreSQL</span> provides these helper functions + to retrieve information from event triggers. + </p><p> + For more information about event triggers, + see <a class="xref" href="event-triggers.html" title="Chapter 40. Event Triggers">Chapter 40</a>. + </p><div class="sect2" id="PG-EVENT-TRIGGER-DDL-COMMAND-END-FUNCTIONS"><div class="titlepage"><div><div><h3 class="title">9.29.1. Capturing Changes at Command End <a href="#PG-EVENT-TRIGGER-DDL-COMMAND-END-FUNCTIONS" class="id_link">#</a></h3></div></div></div><a id="id-1.5.8.35.4.2" class="indexterm"></a><pre class="synopsis"> +<code class="function">pg_event_trigger_ddl_commands</code> () → <code class="returnvalue">setof record</code> +</pre><p> + <code class="function">pg_event_trigger_ddl_commands</code> returns a list of + <acronym class="acronym">DDL</acronym> commands executed by each user action, + when invoked in a function attached to a + <code class="literal">ddl_command_end</code> event trigger. If called in any other + context, an error is raised. + <code class="function">pg_event_trigger_ddl_commands</code> returns one row for each + base command executed; some commands that are a single SQL sentence + may return more than one row. This function returns the following + columns: + + </p><div class="informaltable"><table class="informaltable" border="1"><colgroup><col /><col /><col /></colgroup><thead><tr><th>Name</th><th>Type</th><th>Description</th></tr></thead><tbody><tr><td><code class="literal">classid</code></td><td><code class="type">oid</code></td><td>OID of catalog the object belongs in</td></tr><tr><td><code class="literal">objid</code></td><td><code class="type">oid</code></td><td>OID of the object itself</td></tr><tr><td><code class="literal">objsubid</code></td><td><code class="type">integer</code></td><td>Sub-object ID (e.g., attribute number for a column)</td></tr><tr><td><code class="literal">command_tag</code></td><td><code class="type">text</code></td><td>Command tag</td></tr><tr><td><code class="literal">object_type</code></td><td><code class="type">text</code></td><td>Type of the object</td></tr><tr><td><code class="literal">schema_name</code></td><td><code class="type">text</code></td><td> + Name of the schema the object belongs in, if any; otherwise <code class="literal">NULL</code>. + No quoting is applied. + </td></tr><tr><td><code class="literal">object_identity</code></td><td><code class="type">text</code></td><td> + Text rendering of the object identity, schema-qualified. Each + identifier included in the identity is quoted if necessary. + </td></tr><tr><td><code class="literal">in_extension</code></td><td><code class="type">boolean</code></td><td>True if the command is part of an extension script</td></tr><tr><td><code class="literal">command</code></td><td><code class="type">pg_ddl_command</code></td><td> + A complete representation of the command, in internal format. + This cannot be output directly, but it can be passed to other + functions to obtain different pieces of information about the + command. + </td></tr></tbody></table></div><p> + </p></div><div class="sect2" id="PG-EVENT-TRIGGER-SQL-DROP-FUNCTIONS"><div class="titlepage"><div><div><h3 class="title">9.29.2. Processing Objects Dropped by a DDL Command <a href="#PG-EVENT-TRIGGER-SQL-DROP-FUNCTIONS" class="id_link">#</a></h3></div></div></div><a id="id-1.5.8.35.5.2" class="indexterm"></a><pre class="synopsis"> +<code class="function">pg_event_trigger_dropped_objects</code> () → <code class="returnvalue">setof record</code> +</pre><p> + <code class="function">pg_event_trigger_dropped_objects</code> returns a list of all objects + dropped by the command in whose <code class="literal">sql_drop</code> event it is called. + If called in any other context, an error is raised. + This function returns the following columns: + + </p><div class="informaltable"><table class="informaltable" border="1"><colgroup><col /><col /><col /></colgroup><thead><tr><th>Name</th><th>Type</th><th>Description</th></tr></thead><tbody><tr><td><code class="literal">classid</code></td><td><code class="type">oid</code></td><td>OID of catalog the object belonged in</td></tr><tr><td><code class="literal">objid</code></td><td><code class="type">oid</code></td><td>OID of the object itself</td></tr><tr><td><code class="literal">objsubid</code></td><td><code class="type">integer</code></td><td>Sub-object ID (e.g., attribute number for a column)</td></tr><tr><td><code class="literal">original</code></td><td><code class="type">boolean</code></td><td>True if this was one of the root object(s) of the deletion</td></tr><tr><td><code class="literal">normal</code></td><td><code class="type">boolean</code></td><td> + True if there was a normal dependency relationship + in the dependency graph leading to this object + </td></tr><tr><td><code class="literal">is_temporary</code></td><td><code class="type">boolean</code></td><td> + True if this was a temporary object + </td></tr><tr><td><code class="literal">object_type</code></td><td><code class="type">text</code></td><td>Type of the object</td></tr><tr><td><code class="literal">schema_name</code></td><td><code class="type">text</code></td><td> + Name of the schema the object belonged in, if any; otherwise <code class="literal">NULL</code>. + No quoting is applied. + </td></tr><tr><td><code class="literal">object_name</code></td><td><code class="type">text</code></td><td> + Name of the object, if the combination of schema and name can be + used as a unique identifier for the object; otherwise <code class="literal">NULL</code>. + No quoting is applied, and name is never schema-qualified. + </td></tr><tr><td><code class="literal">object_identity</code></td><td><code class="type">text</code></td><td> + Text rendering of the object identity, schema-qualified. Each + identifier included in the identity is quoted if necessary. + </td></tr><tr><td><code class="literal">address_names</code></td><td><code class="type">text[]</code></td><td> + An array that, together with <code class="literal">object_type</code> and + <code class="literal">address_args</code>, can be used by + the <code class="function">pg_get_object_address</code> function to + recreate the object address in a remote server containing an + identically named object of the same kind. + </td></tr><tr><td><code class="literal">address_args</code></td><td><code class="type">text[]</code></td><td> + Complement for <code class="literal">address_names</code> + </td></tr></tbody></table></div><p> + </p><p> + The <code class="function">pg_event_trigger_dropped_objects</code> function can be used + in an event trigger like this: +</p><pre class="programlisting"> +CREATE FUNCTION test_event_trigger_for_drops() + RETURNS event_trigger LANGUAGE plpgsql AS $$ +DECLARE + obj record; +BEGIN + FOR obj IN SELECT * FROM pg_event_trigger_dropped_objects() + LOOP + RAISE NOTICE '% dropped object: % %.% %', + tg_tag, + obj.object_type, + obj.schema_name, + obj.object_name, + obj.object_identity; + END LOOP; +END; +$$; +CREATE EVENT TRIGGER test_event_trigger_for_drops + ON sql_drop + EXECUTE FUNCTION test_event_trigger_for_drops(); +</pre><p> + </p></div><div class="sect2" id="PG-EVENT-TRIGGER-TABLE-REWRITE-FUNCTIONS"><div class="titlepage"><div><div><h3 class="title">9.29.3. Handling a Table Rewrite Event <a href="#PG-EVENT-TRIGGER-TABLE-REWRITE-FUNCTIONS" class="id_link">#</a></h3></div></div></div><p> + The functions shown in + <a class="xref" href="functions-event-triggers.html#FUNCTIONS-EVENT-TRIGGER-TABLE-REWRITE" title="Table 9.104. Table Rewrite Information Functions">Table 9.104</a> + provide information about a table for which a + <code class="literal">table_rewrite</code> event has just been called. + If called in any other context, an error is raised. + </p><div class="table" id="FUNCTIONS-EVENT-TRIGGER-TABLE-REWRITE"><p class="title"><strong>Table 9.104. Table Rewrite Information Functions</strong></p><div class="table-contents"><table class="table" summary="Table Rewrite Information Functions" border="1"><colgroup><col /></colgroup><thead><tr><th class="func_table_entry"><p class="func_signature"> + Function + </p> + <p> + Description + </p></th></tr></thead><tbody><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.35.6.3.2.2.1.1.1.1" class="indexterm"></a> + <code class="function">pg_event_trigger_table_rewrite_oid</code> () + → <code class="returnvalue">oid</code> + </p> + <p> + Returns the OID of the table about to be rewritten. + </p></td></tr><tr><td class="func_table_entry"><p class="func_signature"> + <a id="id-1.5.8.35.6.3.2.2.2.1.1.1" class="indexterm"></a> + <code class="function">pg_event_trigger_table_rewrite_reason</code> () + → <code class="returnvalue">integer</code> + </p> + <p> + Returns a code explaining the reason(s) for rewriting. The exact + meaning of the codes is release dependent. + </p></td></tr></tbody></table></div></div><br class="table-break" /><p> + These functions can be used in an event trigger like this: +</p><pre class="programlisting"> +CREATE FUNCTION test_event_trigger_table_rewrite_oid() + RETURNS event_trigger + LANGUAGE plpgsql AS +$$ +BEGIN + RAISE NOTICE 'rewriting table % for reason %', + pg_event_trigger_table_rewrite_oid()::regclass, + pg_event_trigger_table_rewrite_reason(); +END; +$$; + +CREATE EVENT TRIGGER test_table_rewrite_oid + ON table_rewrite + EXECUTE FUNCTION test_event_trigger_table_rewrite_oid(); +</pre><p> + </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="functions-trigger.html" title="9.28. Trigger Functions">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="functions.html" title="Chapter 9. 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