<programlisting>

CREATE TRIGGER insert_measurement_trigger

BEFORE INSERT ON measurement

FOR EACH ROW EXECUTEPROCEDURE measurement_insert_trigger();

FOR EACH ROW EXECUTEFUNCTION measurement_insert_trigger();

</programlisting>

We must redefine the trigger function each month so that it always

AS 'noddl' LANGUAGE C;

CREATE EVENT TRIGGER noddl ON ddl_command_start

EXECUTEPROCEDURE noddl();

EXECUTEFUNCTION noddl();

</programlisting>

</para>

CREATE EVENT TRIGGER no_rewrite_allowed

ON table_rewrite

EXECUTEPROCEDURE no_rewrite();

EXECUTEFUNCTION no_rewrite();

</programlisting>

</para>

</sect1>

<programlisting>

CREATE TRIGGER z_min_update

BEFORE UPDATE ON tablename

FOR EACH ROW EXECUTEPROCEDURE suppress_redundant_updates_trigger();

FOR EACH ROW EXECUTEFUNCTION suppress_redundant_updates_trigger();

</programlisting>

In most cases, you would want to fire this trigger last for each row.

Bearing in mind that triggers fire in name order, you would then

$$;

CREATE EVENT TRIGGER test_event_trigger_for_drops

ON sql_drop

EXECUTEPROCEDURE test_event_trigger_for_drops();

EXECUTEFUNCTION test_event_trigger_for_drops();

</programlisting>

</para>

</sect2>

CREATE EVENT TRIGGER test_table_rewrite_oid

ON table_rewrite

EXECUTEPROCEDURE test_event_trigger_table_rewrite_oid();

EXECUTEFUNCTION test_event_trigger_table_rewrite_oid();

</programlisting>

</para>

</sect2>

<entry><type>character_data</type></entry>

<entry>

Statement that is executed by the trigger (currently always

<literal>EXECUTEPROCEDURE

<literal>EXECUTEFUNCTION

<replaceable>function</replaceable>(...)</literal>)

</entry>

</row>

CREATE TABLE image (title text, raster lo);

CREATE TRIGGER t_raster BEFORE UPDATE OR DELETE ON image

FOR EACH ROW EXECUTEPROCEDURE lo_manage(raster);

FOR EACH ROW EXECUTEFUNCTION lo_manage(raster);

</programlisting>

<para>

CREATE TRIGGER test_valid_id_trig

BEFORE INSERT OR UPDATE ON test

FOR EACH ROW EXECUTEPROCEDURE valid_id();

FOR EACH ROW EXECUTEFUNCTION valid_id();

</programlisting>

</para>

</sect1>

CREATE EVENT TRIGGER perl_a_snitch

ON ddl_command_start

EXECUTEPROCEDURE perlsnitch();

EXECUTEFUNCTION perlsnitch();

</programlisting>

</para>

</sect1>

$emp_stamp$ LANGUAGE plpgsql;

CREATE TRIGGER emp_stamp BEFORE INSERT OR UPDATE ON emp

FOR EACH ROW EXECUTEPROCEDURE emp_stamp();

FOR EACH ROW EXECUTEFUNCTION emp_stamp();

</programlisting>

</example>

CREATE TRIGGER emp_audit

AFTER INSERT OR UPDATE OR DELETE ON emp

FOR EACH ROW EXECUTEPROCEDURE process_emp_audit();

FOR EACH ROW EXECUTEFUNCTION process_emp_audit();

</programlisting>

</example>

CREATE TRIGGER emp_audit

INSTEAD OF INSERT OR UPDATE OR DELETE ON emp_view

FOR EACH ROW EXECUTEPROCEDURE update_emp_view();

FOR EACH ROW EXECUTEFUNCTION update_emp_view();

</programlisting>

</example>

CREATE TRIGGER maint_sales_summary_bytime

AFTER INSERT OR UPDATE OR DELETE ON sales_fact

FOR EACH ROW EXECUTEPROCEDURE maint_sales_summary_bytime();

FOR EACH ROW EXECUTEFUNCTION maint_sales_summary_bytime();

INSERT INTO sales_fact VALUES(1,1,1,10,3,15);

INSERT INTO sales_fact VALUES(1,2,1,20,5,35);

CREATE TRIGGER emp_audit_ins

AFTER INSERT ON emp

REFERENCING NEW TABLE AS new_table

FOR EACH STATEMENT EXECUTEPROCEDURE process_emp_audit();

FOR EACH STATEMENT EXECUTEFUNCTION process_emp_audit();

CREATE TRIGGER emp_audit_upd

AFTER UPDATE ON emp

REFERENCING OLD TABLE AS old_table NEW TABLE AS new_table

FOR EACH STATEMENT EXECUTEPROCEDURE process_emp_audit();

FOR EACH STATEMENT EXECUTEFUNCTION process_emp_audit();

CREATE TRIGGER emp_audit_del

AFTER DELETE ON emp

REFERENCING OLD TABLE AS old_table

FOR EACH STATEMENT EXECUTEPROCEDURE process_emp_audit();

FOR EACH STATEMENT EXECUTEFUNCTION process_emp_audit();

</programlisting>

</example>

END;

$$ LANGUAGE plpgsql;

CREATE EVENT TRIGGER snitch ON ddl_command_start EXECUTEPROCEDURE snitch();

CREATE EVENT TRIGGER snitch ON ddl_command_start EXECUTEFUNCTION snitch();

</programlisting>

</example>

</sect2>

CREATE TABLE mytab (num integer, description text, modcnt integer);

CREATE TRIGGER trig_mytab_modcount BEFORE INSERT OR UPDATE ON mytab

FOR EACH ROW EXECUTEPROCEDURE trigfunc_modcount('modcnt');

FOR EACH ROW EXECUTEFUNCTION trigfunc_modcount('modcnt');

</programlisting>

Notice that the trigger function itself does not know the column

elog NOTICE "tclsnitch: $TG_event $TG_tag"

$$ LANGUAGE pltcl;

CREATE EVENT TRIGGER tcl_a_snitch ON ddl_command_start EXECUTEPROCEDURE tclsnitch();

CREATE EVENT TRIGGER tcl_a_snitch ON ddl_command_start EXECUTEFUNCTION tclsnitch();

</programlisting>

</para>

</sect1>

CREATE EVENT TRIGGER <replaceable class="parameter">name</replaceable>

ON <replaceable class="parameter">event</replaceable>

[ WHEN <replaceable class="parameter">filter_variable</replaceable> IN (filter_value [, ... ]) [ AND ... ] ]

EXECUTE PROCEDURE <replaceable class="parameter">function_name</replaceable>()

EXECUTE{ FUNCTION |PROCEDURE } <replaceable class="parameter">function_name</replaceable>()

</synopsis>

</refsynopsisdiv>

A user-supplied function that is declared as taking no argument and

returning type <literal>event_trigger</literal>.

</para>

<para>

In the syntax of <literal>CREATE EVENT TRIGGER</literal>, the keywords

<literal>FUNCTION</literal> and <literal>PROCEDURE</literal> are

equivalent, but the referenced function must in any case be a function,

not a procedure. The use of the keyword <literal>PROCEDURE</literal>

here is historical and deprecated.

</para>

</listitem>

</varlistentry>

$$;

CREATE EVENT TRIGGER abort_ddl ON ddl_command_start

EXECUTEPROCEDURE abort_any_command();

EXECUTEFUNCTION abort_any_command();

</programlisting></para>

</refsect1>

[ REFERENCING { { OLD | NEW } TABLE [ AS ] <replaceable class="parameter">transition_relation_name</replaceable> } [ ... ] ]

[ FOR [ EACH ] { ROW | STATEMENT } ]

[ WHEN ( <replaceable class="parameter">condition</replaceable> ) ]

EXECUTE PROCEDURE <replaceable class="parameter">function_name</replaceable> ( <replaceable class="parameter">arguments</replaceable> )

EXECUTE{ FUNCTION |PROCEDURE } <replaceable class="parameter">function_name</replaceable> ( <replaceable class="parameter">arguments</replaceable> )

<phrase>where <replaceable class="parameter">event</replaceable> can be one of:</phrase>

and returning type <literal>trigger</literal>, which is executed when

the trigger fires.

</para>

<para>

In the syntax of <literal>CREATE TRIGGER</literal>, the keywords

<literal>FUNCTION</literal> and <literal>PROCEDURE</literal> are

equivalent, but the referenced function must in any case be a function,

not a procedure. The use of the keyword <literal>PROCEDURE</literal>

here is historical and deprecated.

</para>

</listitem>

</varlistentry>

CREATE TRIGGER check_update

BEFORE UPDATE ON accounts

FOR EACH ROW

EXECUTEPROCEDURE check_account_update();

EXECUTEFUNCTION check_account_update();

</programlisting>

The same, but only execute the function if column <literal>balance</literal>

CREATE TRIGGER check_update

BEFORE UPDATE OF balance ON accounts

FOR EACH ROW

EXECUTEPROCEDURE check_account_update();

EXECUTEFUNCTION check_account_update();

</programlisting>

This form only executes the function if column <literal>balance</literal>

BEFORE UPDATE ON accounts

FOR EACH ROW

WHEN (OLD.balance IS DISTINCT FROM NEW.balance)

EXECUTEPROCEDURE check_account_update();

EXECUTEFUNCTION check_account_update();

</programlisting>

Call a function to log updates of <literal>accounts</literal>, but only if

AFTER UPDATE ON accounts

FOR EACH ROW

WHEN (OLD.* IS DISTINCT FROM NEW.*)

EXECUTEPROCEDURE log_account_update();

EXECUTEFUNCTION log_account_update();

</programlisting>

Execute the function <function>view_insert_row</function> for each row to insert

CREATE TRIGGER view_insert

INSTEAD OF INSERT ON my_view

FOR EACH ROW

EXECUTEPROCEDURE view_insert_row();

EXECUTEFUNCTION view_insert_row();

</programlisting>

Execute the function <function>check_transfer_balances_to_zero</function> for each

AFTER INSERT ON transfer

REFERENCING NEW TABLE AS inserted

FOR EACH STATEMENT

EXECUTEPROCEDURE check_transfer_balances_to_zero();

EXECUTEFUNCTION check_transfer_balances_to_zero();

</programlisting>

Execute the function <function>check_matching_pairs</function> for each row to

AFTER UPDATE ON paired_items

REFERENCING NEW TABLE AS newtab OLD TABLE AS oldtab

FOR EACH ROW

EXECUTEPROCEDURE check_matching_pairs();

EXECUTEFUNCTION check_matching_pairs();

</programlisting>

</para>