(语法警告错误)我想在每次特定表发生更改时得到通知,例如插入新行。只要我不尝试通过查询而不是程序来监视SQL Server / SSMS中的队列,它就可以工作。
我创建了一个新的服务并像这样排队:
CREATE QUEUE SQLDependencyQueue;
CREATE SERVICE NamesService
ON QUEUE SQLDependencyQueue
([http://schemas.microsoft.com/SQL/Notifications/PostQueryNotification]) ;
[当我现在用一个小的C#程序收听队列时,它就像一种魅力。
private void InitializGetData()
{
String connectionString = "Server=DESKTOP-N943R2B\\SQLEXPRESS01;Database = DBDependency; User Id = sa;Password = admin; ";
if (conn == null)
{
conn = new SqlConnection(connectionString);
}
if(command == null)
{
command = new SqlCommand(@"SELECT[id],[lade_nr],[vg_lfd_nr],[status] FROM[dbo].[t3_auftr_log_ll] where [status] = 0", conn);
}
if (dataToWatch == null)
{
dataToWatch = new DataSet();
}
notification = new SqlNotificationRequestRegister("WAITFOR(RECEIVE * FROM SQLDependencyQueue);", strServiceName, timeOut, connectionString);
notification.OnChanged += NotificationOnChanged;
getData();
}
void getData()
{
if(notification == null)
{
return;
}
dataToWatch.Clear();
command.Notification = null;
command.Notification = notification.NotificationRequest;
//notification.StartSqlNotification();
using (SqlDataAdapter adapter = new SqlDataAdapter(command))
{
adapter.Fill(dataToWatch, "Order_log_ll");
for(int i= 0; i <= dataToWatch.Tables["Order_log_ll"].Rows.Count - 1; i++)
{
Console.WriteLine(String.Format("Row: {0}", dataToWatch.Tables["t3_Auftr_log_ll"].Rows[i]["vg_lfd_nr"].ToString())); //, dataToWatch.Tables["t3_Auftr_log_ll"].Rows[i]["status"].ToString()
using (SqlCommand cmd = new SqlCommand("update t3_auftr_log_ll set status = 1 where id = @id",conn))
{
if (conn.State != System.Data.ConnectionState.Open)
{
conn.Open();
}
cmd.Parameters.AddWithValue("@id", dataToWatch.Tables["t3_Auftr_log_ll"].Rows[i]["id"].ToString());
cmd.ExecuteNonQuery();
}
}
}
notification.StartSqlNotification();
}
private void RegisterSqlNotificationRequest()
{
request = new SqlNotificationRequest();
request.UserData = new Guid().ToString();
request.Options = String.Format("Service={0}", strServiceName);
request.Timeout = intNotificationTimeout;
if (OnChanged != null)
{
OnChanged(this, null);
}
}
public void Listen()
{
using (SqlConnection conn = new SqlConnection(strConnectionString))
{
using (cmd = new SqlCommand("WAITFOR(RECEIVE * FROM SQLDependencyQueue);", conn))
{
if (conn.State != System.Data.ConnectionState.Open)
{
conn.Open();
}
cmd.CommandTimeout = intNotificationTimeout + 120;
using (SqlDataReader reader = cmd.ExecuteReader())
{
while (reader.Read())
{
for (int i = 0; i <= reader.FieldCount - 1; i++)
Debug.WriteLine(reader[i].ToString());
}
}
}
}
RegisterSqlNotificationRequest();
}
但是如果我启动程序,然后在SSMS中调用查询以查看队列中包含的内容,如下所示:
WAITFOR(RECEIVE * FROM SQLDependencyQueue);
或类似的东西:
RECEIVE conversation_handle, message_type_name, message_body
FROM SQLDependencyQueue;
队列停止工作。我的程序正在等待通知,但是当我在表中插入内容时,SQL Server不再在此之后创建通知。
当我检查队列是否处于活动状态时:
select is_receive_enabled
from sys.service_queues
where name = N'SQLDependencyQueue';
显示为活动状态为“ 1”,但仍未收到通知。
仅当我重新启动程序并再次订阅队列时,它才能再次工作。
如果您手动运行RECEIVE
并收到一条消息,则表示您已经使用了通知。在您的C#代码中,使用了通知后,您再次订阅。如果您从SSMS使用它,则您的程序将不再订阅,因此该程序将永远等待已从队列中使用的通知,并且没人会重新订阅。
您可以检查sys.dm_qn_subscriptions
查询通知的状态订阅。