拷贝个例子给你
CREATE OR REPLACE TRIGGER emp_SalUp
AFTER UPDATE OF sal ON emp
FOR EACH ROW
DECLARE
vsal NUMBER;
BEGIN
vsal:=NVL(:NEW.sal,0)-NVL(:OLD.sal,0);
IF vsal<=0 THEN
RAISE_APPLICATION_ERROR(-20001,'Increased Salary is not zero and littler than zero');
END IF;
END;
/
CREATE OR REPLACE TRIGGER emp_SalUp
AFTER UPDATE OF sal ON emp
FOR EACH ROW
DECLARE
vsal NUMBER;
BEGIN
vsal:=NVL(:NEW.sal,0)-NVL(:OLD.sal,0);
IF vsal<=0 THEN
RAISE_APPLICATION_ERROR(-20001,'Increased Salary is not zero and littler than zero');
END IF;
END;
/
before update on b
for each row
as
if :new.col_name<>:old.col_name then
...
end if; --这样比较麻烦,要每个来作比较
end;
/对于oracle要找出那个被更新字段有难度