Question

我正在尝试编写一个触发器，如下面的简化示例所示：

create trigger adr_trg update of fname, lname on adr
REFERENCING OLD AS o NEW AS n
FOR EACH ROW
(
  IF o.fname <> n.fname THEN
    insert into adrlog (old_value, new_value)
    values (o.fname, n.fname);
  END IF;

  IF o.lname <> n.lname THEN
    insert into adrlog (old_value, new_value)
    values (o.lname, n.lname);
  END IF;
)

这失败了！

只有这样才有效：

create trigger adr_trg update of fname, lname on adr
REFERENCING OLD AS o NEW AS n
FOR EACH ROW
(
    insert into adrlog (old_value, new_value)
    values (o.fname, n.fname);
)

我做错了什么？

Answer 1

我认为你应该用IF-THEN逻辑编写一个存储过程，然后从这个触发器中调用它。我认为触发器只支持简单的SQL语句，而不支持SPL语句

编辑：

CREATE PROCEDURE proc1()
REFERENCING OLD AS o NEW AS n FOR tab1; 
....your logic


CREATE TRIGGER adr_trg update of fname, lname on adr
REFERENCING OLD AS o NEW AS n
  FOR EACH ROW(EXECUTE PROCEDURE proc1() WITH TRIGGER REFERENCES);

Answer 2

老问题，但没有得到很好的回答，以防有人像我一样在这里降落。

Informix处理所请求的功能，但语法不同：

create trigger adr_trg update of fname,lname on adr 
 referencing old as o new as n
    for each row
    when ( o.fname != n.fname )
    (
      insert into adrlog (old_value,new_value)
        values (o.fname,n.fname)
    ) ,
    when ( o.lname != n.lname )
    (
      insert into adrlog (old_value,new_value)
        values (o.lname,n.lname)
    )
;

如何在informix中创建触发器？

2 个答案: