怎么使用C#代码实现数据库触发器的功能

如何使用C#代码实现数据库触发器的功能
之前使用SQL的触发器来实现触发功能 如 删除入库单时从物料表的库存中减去相应的数量.

但如果我要改成用业务逻辑层代码实现此功能的话要怎么写.谢谢

[解决办法]
事件
[解决办法]

C# code

using System;namespace ConsoleApplication1{    class Program    {        static void Main(string[] args)        {            Bank b = new Bank();            b.BeforeClosed +=new Bank.BeforeBankCloseHandler(b_BeforeClosed);            b.Close();        }        static void b_BeforeClosed(object sender, BeforeBankCloseEventArgs e)        {            Console.WriteLine("Bank'Name is:"+e.BankName);            Console.WriteLine("Before bank is closed,I can do something");        }    }    public class Bank    {        public delegate void BeforeBankCloseHandler(object sender, BeforeBankCloseEventArgs e);        public event BeforeBankCloseHandler BeforeClosed;        public void Close()        {            string bName = "China Bank";            BeforeBankCloseEventArgs arg = new BeforeBankCloseEventArgs(bName);            BeforeClosed(this, arg);            Console.WriteLine("Bank Closed");        }    }    public class BeforeBankCloseEventArgs : EventArgs    {        public BeforeBankCloseEventArgs(string m)        {            _bankName = m;        }        private string _bankName;        public string BankName        {            get { return _bankName; }            set { _bankName = value; }        }    }}
[解决办法]
http://topic.csdn.net/u/20090227/16/9f795a88-45b5-47c7-b68e-a83ae0d74fd8.html