DROP TEXT SEARCH PARSER
Описание
DROP TEXT SEARCH PARSER удаляет существующий анализатор текстового поиска. Выполнить эту команду может только суперпользователь.
Параметры
- IF EXISTS
Не считать ошибкой, если анализатор текстового поиска не существует. В этом случае будет выдано замечание.
- имя
Имя (возможно, дополненное схемой) существующего анализатора текстового поиска.
- CASCADE
Автоматически удалять объекты, зависящие от данного анализатора текстового поиска.
- RESTRICT
Отказать в удалении анализатора текстового поиска, если от него зависят какие-либо объекты. Это поведение по умолчанию.
Примеры
Удаление анализатора текстового поиска my_parser:
DROP TEXT SEARCH PARSER my_parser;
Эта команда не будет выполнена, если существуют конфигурации текстового поиска, использующие это анализатор. Чтобы удалить такие конфигурации вместе с анализатором, следует добавить указание CASCADE.
Пред. | Начало | След. |
DROP TEXT SEARCH DICTIONARY | Уровень выше | DROP TEXT SEARCH TEMPLATE |
CREATE EVENT TRIGGER
CREATE EVENT TRIGGER — define a new event trigger
Synopsis
CREATE EVENT TRIGGERname
ONevent
[ WHENfilter_variable
IN (filter_value
[, ... ]) [ AND ... ] ] EXECUTE { FUNCTION | PROCEDURE }function_name
()
Description
CREATE EVENT TRIGGER
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.
Parameters
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
isTAG
.filter_value
A list of values for the associated
filter_variable
for which the trigger should fire. ForTAG
, 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 keywordsFUNCTION
andPROCEDURE
are equivalent, but the referenced function must in any case be a function, not a procedure. The use of the keywordPROCEDURE
here is historical and deprecated.
Notes
Only superusers can create event triggers.
Event triggers are disabled in single-user mode (see postgres) 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.
Examples
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();
Compatibility
There is no CREATE EVENT TRIGGER
statement in the SQL standard.