更新/插入触发器之前的Postgresql似乎不起作用

Question

我有以下触发功能:

CREATE OR REPLACE FUNCTION update_modelname_function()
  RETURNS trigger AS
$BODY$
BEGIN
  IF tg_op = 'INSERT' THEN
     new.model_name := upper(new.model_name);
     RETURN new;
  END IF;
  IF tg_op = 'UPDATE' THEN
     old.model_name := upper(old.model_name);
     RETURN new;
  END IF;
END
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;

我想要实现的是当列model_name的值在表中持久化时始终是大写的.但似乎没有任何事情发生.有任何想法吗？

Answer 1

你意外更新old而不是new.尝试:

CREATE OR REPLACE FUNCTION update_modelname_function()
  RETURNS trigger AS
$BODY$
BEGIN
  IF tg_op = 'INSERT' THEN
     new.model_name := upper(new.model_name);
     RETURN new;
  ELSIF tg_op = 'UPDATE' THEN
     new.model_name := upper(new.model_name);
     RETURN new;
  END IF;
END
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;

如果示例显示整个代码,并且实际触发器仅触发INSERT和/或UPDATE您可以进一步简化:

CREATE OR REPLACE FUNCTION update_modelname_function()
  RETURNS trigger AS
$BODY$
BEGIN

new.model_name := upper(new.model_name);
RETURN new;

END
$BODY$
  LANGUAGE plpgsql VOLATILE;