System.Data.SqlClient.SqlDependency is ideal for caching scenarios, where your ASP.NET application or middle-tier service needs to keep certain information cached in memory. System.Data.SqlClient.SqlDependency allows you to receive notifications when the original data in the database changes so that the cache can be refreshed.

To set up a dependency, you need to associate a System.Data.SqlClient.SqlDependency object to one or more System.Data.SqlClient.SqlCommand objects. To receive notifications, you need to subscribe to the SqlDependency.OnChange event. For more information about the requirements for creating queries for notifications, see "Creating a Query for Notification" in SQL Server Books Online.

For more information, see Using Query Notifications and "Building Notification Solutions" in SQL Server Books Online.

Query notifications are supported only for SELECT statements that meet a list of specific requirements. The following table provides links to the Service Broker and Query Notifications documentation in SQL Server Books Online.

SQL Server Books Online

• tp://msdn.microsoft.com/library/ms181122.aspx

• tp://msdn.microsoft.com/library/ms166059.aspx

• tp://msdn.microsoft.com/library/bb522911.aspx

• tp://msdn.microsoft.com/library/ms172604.aspx

• tp://msdn.microsoft.com/library/ms188311.aspx

• tp://msdn.microsoft.com/library/ms166028.aspx

• tp://msdn.microsoft.com/library/bb522899.aspx

• tp://msdn.microsoft.com/library/ms166100.aspx

• tp://msdn.microsoft.com/library/bb522908.aspx

Namespace: System.Data.SqlClient
Assembly: System.Data (in System.Data.dll)
Assembly Versions: 2.0.0.0