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by Roy Osherove.
Original Post: Yukon "Query Notification": a life saver
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At the Israeli SQL user group today we had a special visit: Roger Woter - PM at Microsoft. he talked about the Service broker in Yukon. very cool stuff. However I learned a little thing that I think is absolutely fabulous:
One of the coolest new features to me in Yukon will be a little thing called "Query Notification". What's that?
I'll give you a hint.
Ever used the ASP.Net Cache object? you know how it has a cache expiry period that can be based upon a time span or a file changing on disk? What's the thing missing most from this functionality? that's right - auto-expiry when the data that you cached changes in the database. It's just not there. People have to go through hoops to find out when data has changed. Not anymore.
With Yukon you can "signal" to the server with the same query that you used to fetch the data you have in memory, and if any row in one of the tables that is in the query is changed, inserted or deleted (meaning running the query now will yield different results) you'll get an automatic notification of this that will be sent to a special queue on which you can listen on and re-cache your query with the new data. no more hopping around trying to know if something changed.