触发器

触发器:
create tringger test
before – 触发时间 after / before
update – 监视动作 insert delete update select ..
on Table – 监视库
for each row – MySql 行级别触发器
begin
DECLARE a int default ‘0’ – 定义变量
update a set nRow= a – 触发事件 insert new.xxx update new.xxx old.xxx delete old.xxx
end