Solved
How to setup validation to check if the input value duplicate in a data page record?
I have a Data Page called CarList. And in the case creation form there is a "carID" input field. I would like to add a validation so that the form can return warning and not to proceed if the user entered a duplicated carID. But I cannot find a suitable function in validation to do the checking with the data page. Anyone has faced this issue before or has any suggestion on that? Thanks.