Constraint Evaluation and Field Validation
The aim of field validation is to check as soon as possible if newly entered or changed column values are acceptable, to correct them where necessary and to warn the user if there is a problem.
Domain constraints are evaluated as a result of the field validation routine being executed.
Field validation occurs when the user leaves a field after manipulating (newly entering, or changing) the column value in that field. It also occurs when the user performs another action that implies that field manipulation has finished and is ready for validation. For example, when the field's window is closed, or when the user issues a commit command by choosing File, Save from the menu bar.
Actions specified for the Adjust Change property of the field are executed just before field validation, and actions specified for its Post-change and Post-edit properties just after field validation.