Display Messages When Conditions Are Met
You use a validation rule to display a message when certain conditions are met. When you create a rule, you define the conditions for when the rule should be applied, and define the message that should be displayed.
Validation rules are set at the object level, and not for a specific page. This means that when you define a validation rule for a form, for example, a form for editing the BudgetDetails business object, the rule is applied on every page where that form is used and the conditions are met.
Validation rules are particularly useful when you want to display some type of warning message based on data entered in a form. Suppose you want to display a message reminding the user to update the Budget Amount when the Head Count is more than 1000. You can create a rule that checks the value entered in the Head Count field, and display a message like this in the form:
