ADO Event Model, Synchronous and Asynchronous Operations
The ADO event model supports certain synchronous and asynchronous ADO operations that issue events, or notifications, before the operation starts or after it completes. An event is actually a call to an event handler routine that you define in your application.
Event handlers that are called before the operation starts allow you to examine or modify the operation parameters, and then either cancel the operation or allow it to complete.
Event handlers that are called after an operation completes are especially important because ADO supports asynchronous operations. For example, an application that starts an asynchronous Recordset.Open operation is notified by an execution complete event when the operation concludes.
Using the ADO event model adds some overhead to your application but provides far more flexibility than other methods of dealing with asynchronous operations, such as monitoring the State property of an object with a loop.
See the following topics for more information about events in ADO: