使用SqlDependency监听MSSQL数据库表变化通知

SqlDependency提供了这样一种机制，当被监测的数据库中的数据发生变化时，SqlDependency会自动触发OnChange事件来通知应用程序，从而达到让系统自动更新数据(或缓存)的目的。

首先要对数据库进行配置，配置命令如下：

1.启用Service Broker并查看是否启用成功，is_broker_enabled为1则表明启用成功：

ALTER DATABASE SqlDepTest SET NEW_BROKER WITH ROLLBACK IMMEDIATE;
ALTER DATABASE SqlDepTest SET ENABLE_BROKER;
SELECT is_broker_enabled FROM sys.databases WHERE name = 'SqlDepTest'

2.开启帐号订阅权限，由于sa帐号不支持权限设置，所以需要建立单独的帐号。

use master

GRANT CREATE PROCEDURE TO sqldep
GRANT CREATE QUEUE TO sqldep
GRANT CREATE SERVICE TO sqldep

use master
GRANT SUBSCRIBE QUERY NOTIFICATIONS TO sqldep
exec sp_helprotect NULL, sqldep

C#示例代码如下：

        private const string SQL_CONNECTIONSETTINGS = "";        static void Main(string[] args)        {            //传入连接字符串,启动基于数据库的监听            SqlDependency.Start(SQL_CONNECTIONSETTINGS);            HandleMessage();            Console.Read();        }        /// <summary>        /// 触发处理消息机制        /// </summary>        private static void HandleMessage()        {            using (SqlConnection connection = new SqlConnection(SQL_CONNECTIONSETTINGS))            {                //依赖是基于某一张表的,而且查询语句只能是简单查询语句,不能带top或*,同时必须指定所有者,即类似[dbo].[]                using (SqlCommand command = new SqlCommand("SELECT [MessageID],[Messages],[CreateTime] FROM [dbo].[Messages]", connection))                {                    int messageID = 0;                    command.CommandType = CommandType.Text;                    connection.Open();                    command.Notification = null;                    SqlDependency dependency = new SqlDependency(command);                    dependency.OnChange += new OnChangeEventHandler(Dependency_OnChange);                    SqlDataReader sdr = command.ExecuteReader();                    while (sdr.Read())                    {                        int.TryParse(sdr["MessageID"].ToString(), out messageID);                        ProcessMessage(messageID);                        Console.WriteLine("MessageID:{0}\tMessages:{1}\tCreateTime:\t{2}", sdr["MessageID"].ToString(), sdr["Messages"].ToString(), sdr["CreateTime"].ToString());                        CompleteProcessMessage(messageID, 2);                    }                    sdr.Close();                }            }        }        /// <summary>        /// SQL消息触发事件        /// </summary>        /// <param name="sender"></param>        /// <param name="e"></param>        private static void Dependency_OnChange(object sender, SqlNotificationEventArgs e)        {            SqlDependency dependency = sender as SqlDependency;            dependency.OnChange -= Dependency_OnChange;            HandleMessage();        }        /// <summary>        /// 处理消息        /// </summary>        /// <param name="messageID">消息编号</param>        private static void ProcessMessage(int messageID)        {            using (SqlConnection connection = new SqlConnection(SQL_CONNECTIONSETTINGS))            {                string sql = string.Format(@"INSERT INTO [dbo].[MessagesComplete]                               SELECT [MessageID],[Messages],1,[CreateTime],GETDATE()                               FROM [dbo].[Messages] WHERE [MessageID] = {0}                               DELETE FROM [dbo].[Messages] WHERE [MessageID] = {0}", messageID);                using (SqlCommand command = new SqlCommand(sql, connection))                {                    command.CommandType = CommandType.Text;                    connection.Open();                    command.ExecuteNonQuery();                    command.Dispose();                }            }        }        /// <summary>        /// 消息处理完成，更新消息处理状态        /// </summary>        /// <param name="messageID">消息编号</param>        /// <param name="status">状态：1.处理中，2.处理完成，-1.处理失败</param>        private static void CompleteProcessMessage(int messageID, int status)        {            using (SqlConnection connection = new SqlConnection(SQL_CONNECTIONSETTINGS))            {                string sql = string.Format("UPDATE [dbo].[MessagesComplete] SET [Status] = {1} WHERE [MessageID] = {0}", messageID, status);                using (SqlCommand command = new SqlCommand(sql, connection))                {                    command.CommandType = CommandType.Text;                    connection.Open();                    command.ExecuteNonQuery();                    command.Dispose();                }            }        }