CREATE_EVENT_TRIGGER - define a new event trigger

       There is no CREATEEVENTTRIGGER statement in the SQL standard.

CREATEEVENTTRIGGER creates a new event trigger. Whenever the designated event occurs and the WHEN
       condition associated with the trigger, if any, is satisfied, the trigger function will be executed. For a
       general introduction to event triggers, see Chapter 38. The user who creates an event trigger becomes its
       owner.

       Forbid the execution of any DDL command:

           CREATE OR REPLACE FUNCTION abort_any_command()
             RETURNS event_trigger
            LANGUAGE plpgsql
             AS $$
           BEGIN
             RAISE EXCEPTION 'command % is disabled', tg_tag;
           END;
           $$;

           CREATE EVENT TRIGGER abort_ddl ON ddl_command_start
              EXECUTE FUNCTION abort_any_command();

       CREATE_EVENT_TRIGGER - define a new event trigger

       Only superusers can create event triggers.

       Event triggers are disabled in single-user mode (see postgres(1)) as well as when event_triggers is set
       to false. If an erroneous event trigger disables the database so much that you can't even drop the
       trigger, restart with event_triggers set to false to temporarily disable event triggers, or in
       single-user mode, and you'll be able to do that.

name
           The name to give the new trigger. This name must be unique within the database.

       event
           The name of the event that triggers a call to the given function. See Section 38.1 for more
           information on event names.

       filter_variable
           The name of a variable used to filter events. This makes it possible to restrict the firing of the
           trigger to a subset of the cases in which it is supported. Currently the only supported
           filter_variable is TAG.

       filter_value
           A list of values for the associated filter_variable for which the trigger should fire. For TAG, this
           means a list of command tags (e.g., 'DROP FUNCTION').

       function_name
           A user-supplied function that is declared as taking no argument and returning type event_trigger.

           In the syntax of CREATE EVENT TRIGGER, the keywords FUNCTION and PROCEDURE are equivalent, but the
           referenced function must in any case be a function, not a procedure. The use of the keyword PROCEDURE
           here is historical and deprecated.

       ALTER EVENT TRIGGER (ALTER_EVENT_TRIGGER(7)), DROP EVENT TRIGGER (DROP_EVENT_TRIGGER(7)), CREATE FUNCTION
       (CREATE_FUNCTION(7))

PostgreSQL 17.5                                       2025                               CREATEEVENTTRIGGER(7)

       CREATE EVENT TRIGGER name
           ON event
           [ WHEN filter_variable IN (filter_value [, ... ]) [ AND ... ] ]
           EXECUTE { FUNCTION | PROCEDURE } function_name()