如何使用SqlCacheDependency？

Question

我需要为一个表实现SqlCacheDependency,这将依赖于这个查询: SELECT Nickname FROM dbo.[User].

我为此创建了一个方法:

private IEnumerable<string> GetNicknamesFromCache()
    {
        const String cacheValueName = "Nicknames";

        var result = HttpRuntime.Cache.Get(cacheValueName) as List<String>;
        if (result == null)
        {
            result = _repository.GetAllNicknames();

            var connectionString = ConfigurationManager.ConnectionStrings["RepositoryContext"].ConnectionString;
            var sqlConnection = new SqlConnection(connectionString);
            var sqlCommand = new SqlCommand("SELECT Nickname FROM dbo.[User]", sqlConnection);
            var sqlDependency = new SqlCacheDependency(sqlCommand);

            HttpRuntime.Cache.Insert(cacheValueName, result, sqlDependency);
        }

        return result;
    }

但是,当我运行我的应用程序时,它不起作用.我检查了订户列表(sys.dm_qn_subscriptions表),没有记录.

我调查了很多时间,并且已经尝试了各种解决方案,但它们对我不起作用:

• 使用可信连接并为公共角色设置一些权限:

  GRANT CREATE PROCEDURE TO public
GRANT CREATE QUEUE TO public
GRANT CREATE SERVICE TO public
GRANT SUBSCRIBE QUERY NOTIFICATIONS TO public
GRANT SELECT ON OBJECT::dbo.[User] TO public
GRANT RECEIVE ON QueryNotificationErrorsQueue TO public
  

• 使用'sa'登录进行连接

• 使用aspnet_regsql.exe(aspnet_regsql.exe -S localhost -E -ed -d TestTable -et -t User)

• 将配置添加到web.config中的system.webServer:

  <caching>
<sqlCacheDependency enabled="true">
<databases>
<add name="Tmpl" pollTime="5000" connectionStringName="RepositoryContext"/>
</databases>
</sqlCacheDependency>
</caching>
  

• 将SqlDependency.Start()放入Global.asax Application_Start事件中

• 在sql server的不同实例上运行(SQL Server 2008 Express,SQL Server 2008)

但它没有帮助.它仍然无法正常工作.

我如何使其工作？

Answer 1

我已经找到了解决方案.

首先检查是否为您的表启用了Service Broker,并在需要时启用它:

SELECT name, is_broker_enabled FROM sys.databases WHERE name = '<databaseName>'

ALTER DATABASE <databaseName> SET enable_broker WITH ROLLBACK IMMEDIATE

接下来在SQL Server中创建新角色sql_dependency_role,为其授予权限并向用户授予角色:

EXEC sp_addrole 'sql_dependency_role'

GRANT CREATE PROCEDURE to sql_dependency_role
GRANT CREATE QUEUE to sql_dependency_role
GRANT CREATE SERVICE to sql_dependency_role
GRANT REFERENCES on CONTRACT::[http://schemas.microsoft.com/SQL/Notifications/PostQueryNotification] to sql_dependency_role
GRANT VIEW DEFINITION TO sql_dependency_role
GRANT SELECT to sql_dependency_role
GRANT SUBSCRIBE QUERY NOTIFICATIONS TO sql_dependency_role
GRANT RECEIVE ON QueryNotificationErrorsQueue TO sql_dependency_role

EXEC sp_addrolemember 'sql_dependency_role', '<userName>'

之后添加C#代码以便使用SqlCacheDependency或SqlDependency(大多以相同的方式).

我已经改变了我的方法,现在它看起来像这样:

private IEnumerable<string> GetNicknamesFromCache()
    {
        const String cacheValueName = "Nicknames";

        var result = HttpRuntime.Cache.Get(cacheValueName) as List<String>;
        if (result == null)
        {
            result = _repository.GetAllNicknames();

            using (var connection = new SqlConnection(_config.ConnectionString))
            {
                connection.Open();

                SqlDependency.Start(_config.ConnectionString);
                var command = new SqlCommand("SELECT Nickname FROM dbo.[User]", connection);
                var dependency = new SqlCacheDependency(command);
                HttpRuntime.Cache.Insert(cacheValueName, result, dependency);

                command.ExecuteNonQuery();
            }
        }

        return result;
    }

现在它工作正常.

不要忘记调用SqlDependency.Start创建方法之前SqlCacheDependency或SqlDependency并在年底执行你的命令.