What is Sql query notification service?
Query notifications allow you to request notification within a specified time-out period when the underlying data of a query changes. The request for notification specifies the notification options, which include the service name, message text, and time-out value to the server.
How can we know that your query is using indexes or not?
The most reliable test for whether the index is used is to simply fill your database with representative amounts of data and then look at the execution plan. And don’t forget to time the actual execution of the query, while you’re at it!
How are query notifications used in SQL Server?
Query notifications are used for applications that need to refresh displays or caches in response to changes in underlying data. Microsoft SQL Server allows .NET applications to send a command to SQL Server and request notification if executing the same command would produce result sets different from those initially retrieved.
When to use query notifications in ADO.NET?
This feature is particularly useful for applications that provide a cache of information from a database, such as a Web application, and need to be notified when the source data is changed. There are three ways you can implement query notifications using ADO.NET:
What does continuous query notification ( CQN ) do?
Continuous Query Notification (CQN) allows an application to register queries with the database for either object change notification (the default) or query result change notification. An object referenced by a registered query is a registered object.
How does object change notification ( OCN ) work?
An object referenced by a registered query is a registered object. If a query is registered for object change notification (OCN), the database notifies the application whenever a transaction changes an object that the query references and commits, regardless of whether the query result changed.