• Implementing a lookup. When a control (like a DBCombo box) changes value, the change event is trapped to update a data control's query.

• Implementing a master detail relationship. Two data controls are added to a dialog box, one for the master portion and a second for the detail portion. Whenever the first data source changes, the second data source's query is updated through an event handler.

• Trapping errors. Most controls have an error event from which you can write an error handler (see Error Trapping).

For more information, see Mapping Messages to Functions.