數據庫之觸發器

觸發器是一種特殊的存儲過程，下面通過觸發器實現對銀行存取款的操作

---創建觸發器
create trigger tr1 on saveinfo after
insert 
AS
BEGIN
declare		@uid	nvarchar(50)
declare		@type int
declare		@qian float 
declare		@yuer	float 
select @uid = uid,	@type=[type],@qian=[money] from saveinfo
select @yuer= [money] from [userinfo] 
where  uid = @uid
if(@type = 1)		--1表示存款
begin
	update userinfo set [money]	= [money] + @qian where  uid = @uid
end
else
begin
	if(@yuer < @qian)
		begin
			print '餘額不足'
		end
	else
		begin 
			update userinfo set [money] = [money] - @qian where  uid = @uid
		end
end
END 
GO