sql server 2008 - 没有触发器的sqlcachedependency？
我很困惑。
我正在使用这个开源代码片段。我在 SQL Server 中有一个没有任何触发器的表，但 SQLCacheDependency 工作正常。我以为你需要在桌子上安装触发器才能让它工作？！
DateTime localFileTimeStamp = DateTime.Now;
DateTime fileTimeStampInDB;
string cacheKey = string.Format("ImageId_{0}", 1);
object o = Utils.Cache.Get(cacheKey);
if (null == o)
{
// get timestamp from DB
SqlCacheDependency dep;
fileTimeStampInDB = DataLayer.GetTimeStamp(1, out dep);
Utils.Cache.Insert(cacheKey, fileTimeStampInDB, dep, Cache.NoAbsoluteExpiration,
Cache.NoSlidingExpiration);
//, CacheItemPriority.Normal);
//new CacheItemRemovedCallback(WebUtils.CacheItemRemovedCallback));
}
每次我将 timeupdated 字段设置为 getdate() 时，我的代码都会检测到对象 o 再次为空，这是应该的，因为它应该在过时后从缓存中删除，但为什么它还能工作？我刚刚开始学习有关 SQLCacheDependency 的教程，所以也许我在阅读它们时错过了一些东西。
编辑：他们正在使用
SqlCacheDependency dependency = new SqlCacheDependency(command);
，我想这不需要触发器。
如果您不喜欢这种方法并更喜欢其他方法，请随时分享。
I am so puzzled.
I am using this open-source snippet. I have a table without any triggers in SQL Server, and yet the SQLCacheDependency is working fine. I thought you needed triggers on the table for it to work?!
DateTime localFileTimeStamp = DateTime.Now;
DateTime fileTimeStampInDB;
string cacheKey = string.Format("ImageId_{0}", 1);
object o = Utils.Cache.Get(cacheKey);
if (null == o)
{
// get timestamp from DB
SqlCacheDependency dep;
fileTimeStampInDB = DataLayer.GetTimeStamp(1, out dep);
Utils.Cache.Insert(cacheKey, fileTimeStampInDB, dep, Cache.NoAbsoluteExpiration,
Cache.NoSlidingExpiration);
//, CacheItemPriority.Normal);
//new CacheItemRemovedCallback(WebUtils.CacheItemRemovedCallback));
}
Every time I set the timeupdated field to getdate(), my code detects that object o is null again, which it should, because it should be dropped from the cache after once it's outdated but why is it working? I have just started following tutorials on SQLCacheDependency, so maybe I missed something while reading them.
EDIT: They're using
SqlCacheDependency dependency = new SqlCacheDependency(command);
and I guess this does not require triggers.
Please feel free to share if you dislike this approach and prefer some other approach.
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不，您不需要这样的触发器。这一切都在查询通知上完成。阅读该文章，它解释了使用 ADO.NET 设置查询通知的 3 种方式。
正是这些查询通知通知底层结果集的更改。
No, you don't need triggers as such. It's all done on Query Notifications. Have a read through that article, it explains the 3 ways query notifications can be set up using ADO.NET.
It's these query notifications, that notify of changes to the underlying resultset.