sql server主动推送客户端更新数据

小谈需求：

最近工作上接到一个需求，做一个web展示数据的报表，最好能实时更新，不限制所用技术。

第一个问题：web服务器推送给浏览器新数据，一开始我想到的最快的最简单的方法就是 在web页面上js轮询了。因为我们的数据更新频率并不快。 后来觉得这种办法有点太土了。 或许长轮询更有效。  当然长轮询的技术很多了。 java 的dwr,c#的 signalr。c#还可以同过异步请求来自己写长轮询。

遇到的第二个问题，就是数据库如何通知web服务器更新数据，下面便是sql server2008的推送了，通过sql server的触发器，当数据表有变化时（增，删，改）就通过tcp请求服务器，服务器会在启动后开启端口一直监听，随时等待通信请求。当收到请求后，就从数据库读取新数据，推送给浏览器。整体大概就这样。

下面是数据库通知服务器。这是一个 winform的demo ,winfom就相当于我们展示数据的服务器了。

最后demo图:

现在我插入一条数据：

然后再看那个客户端：

刚插入的数据已经出现了哦。

客户端代码：

winform:

程序启动后，开启端口监听，如果有收到通信，则通知 dataview更新数据。

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using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Windows.Forms;
using System.Threading;
 
namespace sql_dependency
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
 
        System.Data.SqlClient.SqlConnection conn = null;
        string _connstr = "Data Source = 10.6.154.251; database=Temp;user id=sa;pwd=MOcyou0543_";
        System.Data.SqlClient.SqlCommand command = null;
 
        private void Form1_Load(object sender, EventArgs e)
        {
            conn = new System.Data.SqlClient.SqlConnection(_connstr);
            command = conn.CreateCommand();
            command.CommandText = "select [A],[B],[C] From [Temp].[dbo].[Simple]";
            SqlDependency.Start(_connstr);//启动
            Thread t = new Thread(new ThreadStart(GetData));
            t.Start();
        }
 
 
        private void GetData()
        {
 
            SetData();
            IPAddress localAddr = IPAddress.Parse("127.0.0.1");
            TcpListener tcplistener = new TcpListener(localAddr, 10010);
            tcplistener.Start();
            byte[] btServerReceive = new byte[2048];
            string strServerReceive = string.Empty;
            while (true)
            {
                TcpClient tcp = tcplistener.AcceptTcpClient();
                Console.WriteLine("Connected!");
                NetworkStream ns = tcp.GetStream();
                int intReceiveLength = ns.Read(btServerReceive, 0, btServerReceive.Length);
                strServerReceive = Encoding.ASCII.GetString(btServerReceive, 0, intReceiveLength);
 
                SetData();
                tcp.Close();
            }
 
        }
        private delegate void ChangeDataView();
        private void SetData()
        {
            if (this.InvokeRequired)
            {
                this.Invoke(new ChangeDataView(SetData));
            }
            else
            {
                using (SqlDataAdapter adapter = new SqlDataAdapter(command)) //查询数据
                {
                    System.Data.DataSet ds = new DataSet();
                    adapter.Fill(ds, 0, 100, "Simple");
                    dataGridView1.DataSource = ds.Tables["Simple"];
                }
 
            }
        }
 
 
 
        private void Form1_Closed(object sender, FormClosedEventArgs e)
        {
            //清理现场
            SqlDependency.Stop(_connstr);
            conn.Close();
            conn.Dispose();
        }
 
 
    }
}

数据库与clr集成，编写写dll：SqlDependency.dll，sql server将在可编程性中加载此dll,

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using System;
using System.IO;
using System.Net;
using System.Net.Sockets;
using Microsoft.SqlServer.Server;
 
using System.Net.Sockets;
namespace SqlDependency
{
    public class Program
    {
 
        [SqlFunction(IsDeterministic = true, DataAccess = DataAccessKind.Read)]
        public static String WriteStringToFile(String FileFullPath, String Contend)
        {
 
            FileInfo Fi = new FileInfo(FileFullPath);
            if (!Fi.Directory.Exists)
            {
                Fi.Directory.Create();
            }
 
            using (StreamWriter rw = File.CreateText(FileFullPath))
            {
 
                rw.WriteLine(Contend);
                TcpClient tcpClient = new TcpClient();
 
                try
                {
                    if (tcpClient == null)
                    {
                        tcpClient = new TcpClient();
                        tcpClient.ReceiveTimeout = 20000;
                    }
                    if (tcpClient.Connected == false)
                    {
                        System.Net.IPAddress address = System.Net.IPAddress.Parse(Contend);
                        System.Net.IPHostEntry ipInfor = System.Net.Dns.GetHostByAddress(address);
                        string hostName = ipInfor.HostName;
                        IPEndPoint serverEndPoint = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 10010);
                        tcpClient.Connect(serverEndPoint);
                        rw.Write(hostName);
                    }
                    rw.Write("连接成功，先发送指令");
                    // Translate the passed message into ASCII and store it as a Byte array.
                    Byte[] data = System.Text.Encoding.ASCII.GetBytes("new data!");
 
                    NetworkStream stream = tcpClient.GetStream();
 
                    // Send the message to the connected TcpServer.
                    stream.Write(data, 0, data.Length);
                    stream.Close();
                 
                }
                catch (Exception e)
                {
                    rw.Write(e.Message);
                }
                tcpClient.Close(); 
                rw.Flush();
                rw.Close();
                return "";
            }
        }
    }
}

接下来，便开始配置sql server啦：

首先开启sql server的clr支持：

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开启数据库CLR 支持
--exec sp_configure 'clr enabled', 1;
--开始数据的验证
alter database dbname set TRUSTWORTHY on;
RECONFIGURE

接着在sql server 2008中，新建查询窗口。加载刚才编写的dll SqlDependency.dll，并注册方法，然后写触发器，当表数据有变化时，触发函数。：

 

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use Temp;--数据库名
create assembly SqlDependency FROM 'D:\SqlDependency.dll'--程序集名称和地址
WITH PERMISSION_SET = UNSAFE
GO
 
--方法名写正确，为程序集中的方法名，注意参数个数
create function WriteStringToFile(@FileFullName as nvarchar(max),  @FileContend AS  nvarchar(max))
returns nvarchar(max)
with returns null on null input
external name [SqlDependency].[SqlDependency.Program].[WriteStringToFile]
GO
 
--编写触发器，传递参数以及
CREATE TRIGGER [dbo].[UserTableChangedEvent] on [dbo].[Simple] 
    FOR INSERT, DELETE, UPDATE 
       
AS 
    BEGIN 
    DECLARE @Contend AS VARCHAR(100) 
    DECLARE @FileName AS VARCHAR(MAX) 
        SET @FileName ='D:\\MSG\\'+CONVERT(varchar(12) , getdate(), 112 )+'\\'+ convert(nvarchar(50), NEWID())+'.TXT' 
          
       SET @Contend = '127.0.0.1'; 
       Select dbo.WriteStringToFile(@FileName, @Contend) 
                   
    END 
  GO

注意，我的应用程序和 数据库在一台服务器上，所以地址都是127.0.0.1.可跟据实际填写正确地址。

再次在sql server中新建一个查询窗口，插入语句，进行测试吧。

如果过程中有问题，需要更新程序，方便地删除之上所创建的几个东东：

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drop TRIGGER [dbo].[UserTableChangedEvent]
drop function WriteStringToFile
drop assembly SqlDependency

之后将尝试在web 结合 signal实现实时推送数据给web页面。等待下篇。

posted @ 2015-04-01 10:26  阿亮的笔记  阅读(2166)  评论(0)    收藏  举报