为什么触发器不工作在Postgresql

Question

我想更新" noofdays ";列，使用下面的触发器。但它不工作，我已经附加了触发器代码和表结构下面

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

您应该触发一个行级触发器:

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