速记 - 实现sql server clr trigger

本来一直反对在sql server中使用clr的，但是无奈在我之前，网站已经被人开启clr，所以今天干脆偶也来实现一个clr的trigger，用于在文章表内建立一个insert 触发器，每次发表文章，均ping一次google的博客接口。

过程如下：

1 建立sql server 项目，选择触发器

2 写代码：

public partial class Triggers

{

// 为目标输入现有表或视图并取消对属性行的注释

[Microsoft.SqlServer.Server.SqlTrigger (Name="Articletrigger", Target="cyzonearticle", Event="FOR INSERT")]

public static void Articletrigger()

{

try

{

SqlTriggerContext triggContext = SqlContext.TriggerContext;

//    SqlParameter userName = new SqlParameter("@username", System.Data.SqlDbType.NVarChar);

if (triggContext.TriggerAction == TriggerAction.Insert)

{

using (SqlConnection conn = new SqlConnection("context connection=true"))

{

conn.Open();

SqlCommand sqlComm = new SqlCommand();

SqlPipe sqlP = SqlContext.Pipe;

sqlComm.Connection = conn;

sqlComm.CommandText = @"select i.articleid,i.userid,i.time,i.publishtype,u.username,u.blogname,u.createtime,dbo.GetLinkUrl(i.articleid,i.publishtype,u.username,i.time) as url from inserted i

inner join userbase u on(i.userid = u.userid)";

DataSet ds = new DataSet();

SqlDataAdapter da = new SqlDataAdapter(sqlComm);

da.Fill(ds);

DataRow dr = ds.Tables[0].Rows[0];

string articleid = dr["articleid"].ToString();

string userid = dr["userid"].ToString();

DateTime time = Convert.ToDateTime(dr["time"]);

string publishtype = dr["publishtype"].ToString();

string username = dr["username"].ToString();

DateTime createtime = Convert.ToDateTime(dr["createtime"]);

string blogname = dr["blogname"].ToString();

string url = dr["url"].ToString();

string rssurl = "";

if (publishtype.ToLower()=="a" || publishtype.ToLower()=="b" || publishtype.ToLower()=="c" )

{

rssurl = "http://www.cyzone.cn/blog/" + username + "/rss.aspx";

}

if ((time - createtime) > new TimeSpan(3, 0, 0, 0))

{

string returns = PingGoogleBlogService(blogname, url, rssurl);

string flag = "0";

if (returns != "Thanks for the ping.")

{

flag = "1";

}

sqlComm.CommandText = "INSERT X_Google_Blog_Ping_Log(articleid,time,flag) VALUES('" + articleid + "','" + time + "','" + flag + "')";

sqlP.Send(sqlComm.CommandText);

sqlP.ExecuteAndSend(sqlComm);

}

}

}

}

catch (Exception ee)

{

System.IO.StreamWriter sw = new System.IO.StreamWriter(@"E:\services\GooglePingDll\xx.txt");

sw.WriteLine(ee.Message+ee.Source);

sw.Close();

}

}

private static string PingGoogleBlogService(string blogname, string url, string rssurl)

{

WebClient w = new WebClient();

Uri uri ;

if (string.IsNullOrEmpty(rssurl))

uri = new Uri("http://blogsearch.google.com/ping?name=" + blogname + "&url=" + url, false);

else

uri = new Uri("http://blogsearch.google.com/ping?name=" + blogname + "&url=" + url+"&changesURL="+rssurl,false);

return w.DownloadString(uri);

}

}

3 编译项目，上传dll到服务器指定目录

4 开启clr（偶的服务器已经默认开启）

5 USE cyzone

GO

EXEC sp_changedbowner 'sa' （更改安全主体，有些服务器不需要）

6 ALTER DATABASE cyzone SET TRUSTWORTHY ON

7 CREATE ASSEMBLY GooleBlogPingService

FROM 'E:"services"GooglePingDll"GoogleBlogPingServiceSqlFunction.dll'

WITH PERMISSION_SET = unSAFE;

8 Create Trigger tr_aasdasd

on cyzonearticle

For INSERT

AS

External Name GooleBlogPingService.Triggers.Articletrigger

Go

其中有几点要注意的是：

如果您的触发器程序中没有访问到数据库服务器的外部资源，可以将权限设置为安全模式，并且略去第5步和第6步

最后一步也是将触发器和程序集挂钩。

这个名称 GooleBlogPingService.Triggers.Articletrigger 是比较讲究的，他的组成是：程序集名称.类名.方法名

that's all.