Validation rules can be applied to custom or standard objects for validating data on insert and update operations. When we perform such operations on a Visualforce page, it uses a standard controller or a custom controller, and that record may cause a validation rule error, which we can display on the Visualforce page as we do on standard pages. A validation rule has two options to select the position for displaying the error for a particular field. If we choose top of the page, the error can be displayed by using the
<apex:messages> component within the
<apex:page> component. If we choose the field option, the error will be shown in the associated field residing ...