I have a entity to save the database of Project Details . In this entity have Start date & End date attributes, I want a validation rule on end date that " Project end date should not be entered earlier than project start date (validation)". How i set this validation rule.
You could implement a microflow instead of the default save button.
In this microflow you can validate the entity you're about to save.
Whenever the entity does not match your conditions, you can use the Validation Feedback to inform the end user what to do.