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<title>31.37.triggers</title>
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<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="sect1" lang="en">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="infoschema-triggers"></a>31.37.<code class="literal">triggers</code></h2></div></div></div>
<p> The view <code class="literal">triggers</code> contains all triggers defined
in the current database that are owned by the current user. (The
owner of the table is the owner of the trigger.)
</p>
<div class="table">
<a name="id702240"></a><p class="title"><b>Table31.35.<code class="literal">triggers</code> Columns</b></p>
<div class="table-contents"><table summary="triggers Columns" border="1">
<colgroup>
<col>
<col>
<col>
</colgroup>
<thead><tr>
<th>Name</th>
<th>Data Type</th>
<th>Description</th>
</tr></thead>
<tbody>
<tr>
<td><code class="literal">trigger_catalog</code></td>
<td><code class="type">sql_identifier</code></td>
<td>Name of the database that contains the trigger (always the current database)</td>
</tr>
<tr>
<td><code class="literal">trigger_schema</code></td>
<td><code class="type">sql_identifier</code></td>
<td>Name of the schema that contains the trigger</td>
</tr>
<tr>
<td><code class="literal">trigger_name</code></td>
<td><code class="type">sql_identifier</code></td>
<td>Name of the trigger</td>
</tr>
<tr>
<td><code class="literal">event_manipulation</code></td>
<td><code class="type">character_data</code></td>
<td> Event that fires the trigger (<code class="literal">INSERT</code>,
<code class="literal">UPDATE</code>, or <code class="literal">DELETE</code>)
</td>
</tr>
<tr>
<td><code class="literal">event_object_catalog</code></td>
<td><code class="type">sql_identifier</code></td>
<td> Name of the database that contains the table that the trigger
is defined on (always the current database)
</td>
</tr>
<tr>
<td><code class="literal">event_object_schema</code></td>
<td><code class="type">sql_identifier</code></td>
<td>Name of the schema that contains the table that the trigger is defined on</td>
</tr>
<tr>
<td><code class="literal">event_object_table</code></td>
<td><code class="type">sql_identifier</code></td>
<td>Name of the table that the trigger is defined on</td>
</tr>
<tr>
<td><code class="literal">action_order</code></td>
<td><code class="type">cardinal_number</code></td>
<td>Not yet implemented</td>
</tr>
<tr>
<td><code class="literal">action_condition</code></td>
<td><code class="type">character_data</code></td>
<td>Applies to a feature not available in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">action_statement</code></td>
<td><code class="type">character_data</code></td>
<td> Statement that is executed by the trigger (currently always
<code class="literal">EXECUTE PROCEDURE
<em class="replaceable"><code>function</code></em>(...)</code>)
</td>
</tr>
<tr>
<td><code class="literal">action_orientation</code></td>
<td><code class="type">character_data</code></td>
<td> Identifies whether the trigger fires once for each processed
row or once for each statement (<code class="literal">ROW</code> or
<code class="literal">STATEMENT</code>)
</td>
</tr>
<tr>
<td><code class="literal">condition_timing</code></td>
<td><code class="type">character_data</code></td>
<td> Time at which the trigger fires (<code class="literal">BEFORE</code> or
<code class="literal">AFTER</code>)
</td>
</tr>
<tr>
<td><code class="literal">condition_reference_old_table</code></td>
<td><code class="type">sql_identifier</code></td>
<td>Applies to a feature not available in <span class="productname">PostgreSQL</span>
</td>
</tr>
<tr>
<td><code class="literal">condition_reference_new_table</code></td>
<td><code class="type">sql_identifier</code></td>
<td>Applies to a feature not available in <span class="productname">PostgreSQL</span>
</td>
</tr>
</tbody>
</table></div>
</div>
<br class="table-break"><p> Triggers in <span class="productname">PostgreSQL</span> have two
incompatibilities with the SQL standard that affect the
representation in the information schema. First, trigger names are
local to the table in <span class="productname">PostgreSQL</span>, rather
than being independent schema objects. Therefore there may be duplicate
trigger names defined in one schema, as long as they belong to
different tables. (<code class="literal">trigger_catalog</code> and
<code class="literal">trigger_schema</code> are really the values pertaining
to the table that the trigger is defined on.) Second, triggers can
be defined to fire on multiple events in
<span class="productname">PostgreSQL</span> (e.g., <code class="literal">ON INSERT OR
UPDATE</code>), whereas the SQL standard only allows one. If a
trigger is defined to fire on multiple events, it is represented as
multiple rows in the information schema, one for each type of
event. As a consequence of these two issues, the primary key of
the view <code class="literal">triggers</code> is really
<code class="literal">(trigger_catalog, trigger_schema, trigger_name,
event_object_table, event_manipulation)</code> instead of
<code class="literal">(trigger_catalog, trigger_schema, trigger_name)</code>,
which is what the SQL standard specifies. Nonetheless, if you
define your triggers in a manner that conforms with the SQL
standard (trigger names unique in the schema and only one event
type per trigger), this will not affect you.
</p>
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