sql server主動推送客戶端更新數據

小談需求：

最近工做上接到一個需求，作一個web展現數據的報表，最好能實時更新，不限制所用技術。

第一個問題：web服務器推送給瀏覽器新數據，一開始我想到的最快的最簡單的方法就是 在web頁面上js輪詢了。由於咱們的數據更新頻率並不快。 後來以爲這種辦法有點太土了。 或許長輪詢更有效。  固然長輪詢的技術不少了。 java 的dwr,c#的 signalr。c#還能夠同過異步請求來本身寫長輪詢。

遇到的第二個問題，就是數據庫如何通知web服務器更新數據，下面即是sql server2008的推送了，經過sql server的觸發器，當數據表有變化時（增，刪，改）就經過tcp請求服務器，服務器會在啓動後開啓端口一直監聽，隨時等待通訊請求。當收到請求後，就從數據庫讀取新數據，推送給瀏覽器。總體大概就這樣。

下面是數據庫通知服務器。這是一個 winform的demo ,winfom就至關於咱們展現數據的服務器了。

最後demo圖:

如今我插入一條數據：

而後再看那個客戶端：

剛插入的數據已經出現了哦。

客戶端代碼：

winform:

程序啓動後，開啓端口監聽，若是有收到通訊，則通知 dataview更新數據。

using System;

02	using System.Collections.Generic;

03	using System.ComponentModel;

04	using System.Data;

05	using System.Data.SqlClient;

06	using System.Drawing;

07	using System.Linq;

08	using System.Net;

09	using System.Net.Sockets;

10	using System.Text;

11	using System.Windows.Forms;

12	using System.Threading;

13

14	namespace sql_dependency

15

{

16	public partial class Form1 : Form

17

{

18	public Form1()

19

{

20	InitializeComponent();

21

}

22

23	System.Data.SqlClient.SqlConnection conn = null;

24	string _connstr = "Data Source = 10.6.154.251; database=Temp;user id=sa;pwd=MOcyou0543_";

25	System.Data.SqlClient.SqlCommand command = null;

26

27	private void Form1_Load(object sender, EventArgs e)

28

{

29	conn = new System.Data.SqlClient.SqlConnection(_connstr);

30	command = conn.CreateCommand();

31	command.CommandText = "select [A],[B],[C] From [Temp].[dbo].[Simple]";

32	SqlDependency.Start(_connstr);//啓動

33	Thread t = new Thread(new ThreadStart(GetData));

34	t.Start();

35

}

36

37

38	private void GetData()

39

{

40

41	SetData();

42	IPAddress localAddr = IPAddress.Parse("127.0.0.1");

43	TcpListener tcplistener = new TcpListener(localAddr, 10010);

44	tcplistener.Start();

45	byte[] btServerReceive = new byte[2048];

46	string strServerReceive = string.Empty;

47	while (true)

48

{

49	TcpClient tcp = tcplistener.AcceptTcpClient();

50	Console.WriteLine("Connected!");

51	NetworkStream ns = tcp.GetStream();

52	int intReceiveLength = ns.Read(btServerReceive, 0, btServerReceive.Length);

53	strServerReceive = Encoding.ASCII.GetString(btServerReceive, 0, intReceiveLength);

54

55	SetData();

56	tcp.Close();

57

}

58

59

}

60	private delegate void ChangeDataView();

61	private void SetData()

62

{

63	if (this.InvokeRequired)

64

{

65	this.Invoke(new ChangeDataView(SetData));

66

}

67

else

68

{

69	using (SqlDataAdapter adapter = new SqlDataAdapter(command)) //查詢數據

70

{

71	System.Data.DataSet ds = new DataSet();

72	adapter.Fill(ds, 0, 100, "Simple");

73	dataGridView1.DataSource = ds.Tables["Simple"];

74

}

75

76

}

77

}

78

79

80

81	private void Form1_Closed(object sender, FormClosedEventArgs e)

82

{

83

//清理現場

84	SqlDependency.Stop(_connstr);

85	conn.Close();

86	conn.Dispose();

87

}

88

89

90

}

91

}   數據庫與clr集成，編寫寫dll：SqlDependency.dll，sql server將在可編程性中加載此dll, 01 using System; 02 using System.IO; 03 using System.Net; 04 using System.Net.Sockets; 05 using Microsoft.SqlServer.Server; 06   07 using System.Net.Sockets; 08 namespace SqlDependency 09 { 10     public class Program 11     { 12   13         [SqlFunction(IsDeterministic = true, DataAccess = DataAccessKind.Read)] 14         public static String WriteStringToFile(String FileFullPath, String Contend) 15         { 16   17             FileInfo Fi = new FileInfo(FileFullPath); 18             if (!Fi.Directory.Exists) 19             { 20                 Fi.Directory.Create(); 21             } 22   23             using (StreamWriter rw = File.CreateText(FileFullPath)) 24             { 25   26                 rw.WriteLine(Contend); 27                 TcpClient tcpClient = new TcpClient(); 28   29                 try 30                 { 31                     if (tcpClient == null) 32                     { 33                         tcpClient = new TcpClient(); 34                         tcpClient.ReceiveTimeout = 20000; 35                     } 36                     if (tcpClient.Connected == false) 37                     { 38                         System.Net.IPAddress address = System.Net.IPAddress.Parse(Contend); 39                         System.Net.IPHostEntry ipInfor = System.Net.Dns.GetHostByAddress(address); 40                         string hostName = ipInfor.HostName; 41                         IPEndPoint serverEndPoint = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 10010); 42                         tcpClient.Connect(serverEndPoint); 43                         rw.Write(hostName); 44                     } 45                     rw.Write("鏈接成功，先發送指令"); 46                     // Translate the passed message into ASCII and store it as a Byte array. 47                     Byte[] data = System.Text.Encoding.ASCII.GetBytes("new data!"); 48   49                     NetworkStream stream = tcpClient.GetStream(); 50   51                     // Send the message to the connected TcpServer. 52                     stream.Write(data, 0, data.Length); 53                     stream.Close();