数据库中读取数据自动生成XML

Program Ex: 
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string sql = "SELECT id,name FROM content FOR XML AUTO,XMLDATA"; 
SqlConnection conn =new SqlConnection( System.Configuration.ConfigurationSettings.AppSettings["testDataBase"] ); 
SqlCommand cmd=new SqlCommand(sql,conn); 
conn.Open(); 
XmlTextReader objXmlReader = (XmlTextReader)cmd.ExecuteXmlReader(); 
DataSet ds = new DataSet(); 
ds.DataSetName = "XML"; 
ds.ReadXml(objXmlReader,XmlReadMode.Fragment); 
ds.WriteXml(Server.MapPath("XML.xml")); 
conn.Close();