Sql 如何在informix中创建触发器？

我正在尝试编写一个触发器，如以下简化示例所示：

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;
)

---

我做错了什么？

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

编辑：

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老问题，但没有很好的回答，以防有人像我一样降落在这里

Informix处理请求的功能，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)
    )
;

---

一个好的商人从不责怪他的工具。在我看来，您需要的条件逻辑最好放在一个过程中。它可能被证明是足够通用的，可以以面向对象的方式用于多个表。您的简化示例肯定表明了这一点。

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);

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)
    )
;