sql - Postgres 触发器创建 - 错误 : no language specified SQL state: 42P13

Question

我是触发器的新手。我正在尝试通过以下链接创建触发器 - http://www.postgresqltutorial.com/creating-first-trigger-postgresql/。但它给出了一些错误。代码块和错误如下。

代码块:

CREATE OR REPLACE FUNCTION log_last_name_changes()
  RETURNS trigger AS
$BODY$
BEGIN
 IF NEW.last_name <> OLD.last_name THEN
 INSERT INTO employee_audits(employee_id,last_name,changed_on)
 VALUES(OLD.id,OLD.last_name,now());
 END IF;
 
 RETURN NEW;
END;
$BODY$

错误:

 ERROR: no language specified
SQL state: 42P13

接下来我可以尝试什么？

Answer 1

试试这个方法:

CREATE OR REPLACE FUNCTION log_last_name_changes()
RETURNS trigger AS
$BODY$
BEGIN
IF NEW.last_name <> OLD.last_name THEN
INSERT INTO employee_audits(employee_id,last_name,changed_on)
VALUES(OLD.id,OLD.last_name,now());
END IF;

RETURN NEW;
END;
$BODY$

LANGUAGE plpgsql VOLATILE -- Says the function is implemented in the plpgsql language; VOLATILE says the function has side effects.
COST 100; -- Estimated execution cost of the function.