Как вставить недавно вставленную строку из одной таблицы в другую таблицу, используя хранимые процедуры и триггеры, используя PostgreSQL?

Question

Моя цель состоит в том, чтобы выполнить запрос таким образом, чтобы в случае добавления или обновления строки в таблице rental это изменение было добавлено в другую таблицу с именем history_rental.

Я написал следующую функцию и триггер:

CREATE OR REPLACE FUNCTION process_rental_audit() RETURNS TRIGGER AS $rental_audit$
    BEGIN
        --
        -- Create a row in rental_audit to reflect the operation performed on emp,
        -- make use of the special variable TG_OP to work out the operation.
        --
        IF (TG_OP = 'UPDATE') THEN
            INSERT INTO history_rental (
                rental_id, memberid, rentalrequestdate, rentalshippeddate, rentalreturneddate, dvdid, dvdtitle, genreid, genrename, ratingid, ratingname
            ) select NEW.rentalid, NEW.memberid, NEW.rentalrequestdate, NEW.rentalshippeddate,
                NEW.rentalreturneddate, dvd.dvdid, dvd.dvdtitle, dvd.genreid, genre.genrename, dvd.ratingid, rating.ratingname from
                rental inner join dvd_copy on NEW.dvd_copy_id=dvd_copy.dvd_copy_id inner join dvd on dvd_copy.dvdid=dvd.dvdid
                inner join rating on rating.ratingid=dvd.ratingid inner join genre on genre.genreid=dvd.genreid ;
            RETURN NEW;
        ELSIF (TG_OP = 'INSERT') THEN
            INSERT INTO history_rental (
                rental_id, memberid, rentalrequestdate, rentalshippeddate, rentalreturneddate, dvdid, dvdtitle, genreid, genrename, ratingid, ratingname
            ) select NEW.rentalid, NEW.memberid, NEW.rentalrequestdate, NEW.rentalshippeddate,
                NEW.rentalreturneddate, dvd.dvdid, dvd.dvdtitle, dvd.genreid, genre.genrename, dvd.ratingid, rating.ratingname from
                rental inner join dvd_copy on NEW.dvd_copy_id=dvd_copy.dvd_copy_id inner join dvd on dvd_copy.dvdid=dvd.dvdid
                inner join rating on rating.ratingid=dvd.ratingid inner join genre on genre.genreid=dvd.genreid ;
            RETURN NEW;
        END IF;
        RETURN NULL; -- result is ignored since this is an AFTER trigger
    END;
$rental_audit$ LANGUAGE plpgsql;


CREATE TRIGGER rental_audit AFTER
INSERT
OR
UPDATE ON rental
FOR EACH ROW EXECUTE PROCEDURE process_rental_audit();

Это работает неправильно. Он вставляет несколько строк.

Перед триггером:

netflix1=# select * from history_rental;
 id | rental_id | memberid | rentalrequestdate | rentalshippeddate | rentalreturneddate | dvdid |       dvdtitle        | genreid | genrename | ratingid | ratingname
----+-----------+----------+-------------------+-------------------+--------------------+-------+-----------------------+---------+-----------+----------+------------
  1 |         3 |        1 | 2019-02-02        | 2019-02-02        | 2019-02-09         |     3 | Catch Me If You Can   |       5 | Drama     |        3 | PG-13
  2 |         6 |       15 | 2019-02-12        | 2019-02-12        | 2019-02-21         |     1 | Groundhog Day         |       3 | Comedy    |        2 | PG
  3 |         2 |        1 | 2019-02-02        | 2019-02-02        | 2019-02-09         |     6 | Mystic River          |       5 | Drama     |        4 | R
  4 |        10 |       15 | 2019-02-28        |                   |                    |     7 | Never Say Never Again |       1 | Action    |        1 | G
  5 |         5 |        5 | 2019-02-15        | 2019-02-15        |                    |     5 | Pale Rider            |      10 | Western   |        4 | R
  6 |         7 |        9 | 2019-02-19        | 2019-02-19        |                    |     2 | The Terminal          |       5 | Drama     |        2 | PG
  7 |         8 |        8 | 2019-02-20        | 2019-02-21        |                    |     2 | The Terminal          |       5 | Drama     |        2 | PG
  8 |         1 |        1 | 2019-02-02        | 2019-02-02        | 2019-02-09         |     4 | The Sixth Sense       |      12 | Horror    |        4 | R
  9 |         4 |        5 | 2019-02-15        | 2019-02-15        |                    |     4 | The Sixth Sense       |      12 | Horror    |        4 | R
 10 |         9 |        1 | 2019-02-20        | 2019-02-20        |                    |     4 | The Sixth Sense       |      12 | Horror    |        4 | R
 11 |        11 |        2 | 2004-02-02        |                   |                    |     4 | The Sixth Sense       |      12 | Horror    |        4 | R
 12 |        12 |        2 | 2004-02-03        |                   |                    |     4 | The Sixth Sense       |      12 | Horror    |        4 | R

После триггера я тестирую с новой фиктивной строкой:

netflix1=# insert into rental values(default, 1, date('2019-03-15'), date('2019-03-15'), date('2019-03-16'), 3);
INSERT 0 1

Но только с добавлением одной строки в rental было добавлено 33 строки:

netflix1=# select * from history_rental;
 id | rental_id | memberid | rentalrequestdate | rentalshippeddate | rentalreturneddate | dvdid |       dvdtitle        | genreid | genrename | ratingid | ratingname
----+-----------+----------+-------------------+-------------------+--------------------+-------+-----------------------+---------+-----------+----------+------------
  1 |         3 |        1 | 2019-02-02        | 2019-02-02        | 2019-02-09         |     3 | Catch Me If You Can   |       5 | Drama     |        3 | PG-13
  2 |         6 |       15 | 2019-02-12        | 2019-02-12        | 2019-02-21         |     1 | Groundhog Day         |       3 | Comedy    |        2 | PG
  3 |         2 |        1 | 2019-02-02        | 2019-02-02        | 2019-02-09         |     6 | Mystic River          |       5 | Drama     |        4 | R
  4 |        10 |       15 | 2019-02-28        |                   |                    |     7 | Never Say Never Again |       1 | Action    |        1 | G
  5 |         5 |        5 | 2019-02-15        | 2019-02-15        |                    |     5 | Pale Rider            |      10 | Western   |        4 | R
  6 |         7 |        9 | 2019-02-19        | 2019-02-19        |                    |     2 | The Terminal          |       5 | Drama     |        2 | PG
  7 |         8 |        8 | 2019-02-20        | 2019-02-21        |                    |     2 | The Terminal          |       5 | Drama     |        2 | PG
  8 |         1 |        1 | 2019-02-02        | 2019-02-02        | 2019-02-09         |     4 | The Sixth Sense       |      12 | Horror    |        4 | R
  9 |         4 |        5 | 2019-02-15        | 2019-02-15        |                    |     4 | The Sixth Sense       |      12 | Horror    |        4 | R
 10 |         9 |        1 | 2019-02-20        | 2019-02-20        |                    |     4 | The Sixth Sense       |      12 | Horror    |        4 | R
 11 |        11 |        2 | 2004-02-02        |                   |                    |     4 | The Sixth Sense       |      12 | Horror    |        4 | R
 12 |        12 |        2 | 2004-02-03        |                   |                    |     4 | The Sixth Sense       |      12 | Horror    |        4 | R
 38 |        15 |        1 | 2019-03-15        | 2019-03-15        | 2019-03-16         |     6 | Mystic River          |       5 | Drama     |        4 | R
 39 |        15 |        1 | 2019-03-15        | 2019-03-15        | 2019-03-16         |     6 | Mystic River          |       5 | Drama     |        4 | R
 40 |        15 |        1 | 2019-03-15        | 2019-03-15        | 2019-03-16         |     6 | Mystic River          |       5 | Drama     |        4 | R
 41 |        15 |        1 | 2019-03-15        | 2019-03-15        | 2019-03-16         |     6 | Mystic River          |       5 | Drama     |        4 | R
 42 |        15 |        1 | 2019-03-15        | 2019-03-15        | 2019-03-16         |     6 | Mystic River          |       5 | Drama     |        4 | R
 43 |        15 |        1 | 2019-03-15        | 2019-03-15        | 2019-03-16         |     6 | Mystic River          |       5 | Drama     |        4 | R
 44 |        15 |        1 | 2019-03-15        | 2019-03-15        | 2019-03-16         |     6 | Mystic River          |       5 | Drama     |        4 | R
 45 |        15 |        1 | 2019-03-15        | 2019-03-15        | 2019-03-16         |     6 | Mystic River          |       5 | Drama     |        4 | R
 46 |        15 |        1 | 2019-03-15        | 2019-03-15        | 2019-03-16         |     6 | Mystic River          |       5 | Drama     |        4 | R
 47 |        15 |        1 | 2019-03-15        | 2019-03-15        | 2019-03-16         |     6 | Mystic River          |       5 | Drama     |        4 | R
 48 |        15 |        1 | 2019-03-15        | 2019-03-15        | 2019-03-16         |     6 | Mystic River          |       5 | Drama     |        4 | R
 49 |        15 |        1 | 2019-03-15        | 2019-03-15        | 2019-03-16         |     6 | Mystic River          |       5 | Drama     |        4 | R
 50 |        15 |        1 | 2019-03-15        | 2019-03-15        | 2019-03-16         |     6 | Mystic River          |       5 | Drama     |        4 | R
(25 rows)

Моя цель - получить только строку с идентификатором 15 выше и все. Я просмотрел некоторые документы и руководства, но тщетно.