This is a general database application problem, the solution for which being provided by the data adapter layer. SQLServer2005, for example, provides a mechanism for notifying a "dependent" that the underlying data has changed, via the SqlDependency class. The basic approach is to assign a dependency to an SqlCommand, and then when the data has changed such that the query associated with the command would yield a different result set, the server issues a notification to registered listeners. The bad news is that this is considered by some to be difficult to implement...there are several hard-to-recognize-at-first-glance caviats; for example, you cannot use a select command like "SELECT * FROM dbo.[Whatever];" because you have to explicitly list the columns, i.e., "SELECT col1, col2, ...". If you google "SqlDependency" you will get some hits that are links to blogs of some folks that were kind enough to enumerate these caviats, presumably making the undertaking a little less painful.