为什么触发器在 Postgresql 中不起作用

Question

我想用下面的触发器更新“noofdays”列。但它不起作用，我在下面附上了触发代码和 table 结构

CREATE OR REPLACE FUNCTION update_days() RETURNS TRIGGER AS $$
  BEGIN
        new."noofdays":=1;
    RETURN new;
  END; 
$$ LANGUAGE plpgsql;

CREATE TRIGGER calc_days before UPDATE ON bookentry FOR EACH STATEMENT EXECUTE PROCEDURE update_days();

 bookid     | integer                     |           |          |
 loginid    | integer                     |           |          |
 borrowtime | timestamp without time zone |           | not null | now()
 returntime | timestamp without time zone |           |          |
 noofdays   | integer                     |           |          |

Answer 1

您需要一个行级触发器：

CREATE TRIGGER calc_days 
   before UPDATE ON bookentry 
   FOR EACH ROW  --<< this
   EXECUTE PROCEDURE update_days();

Answer 2

您应该触发行级触发器：

CREATE TRIGGER calc_days 
before UPDATE ON bookentry 
FOR EACH ROW  --<< this
EXECUTE PROCEDURE update_days();

为什么触发器在 Postgresql 中不起作用

Why the Trigger is not working in Postgresql

postgresql

triggers

psql