How to not make this field unique( should not allow same entry twice)

i added a field in demographics to keep a record of internal serial numbers alloted to pts. but it is allowing entry of same no to more than one pt.
how do i make it unique so that if a pre existing jhc id is there, it shoul throw an error sayign duplicate entry not allowed.

i renamed drivers_license field for thsi purpose which i thought would not allow duplicate entries, but it is allowing.

Hi ruth, i cannot find the drop down from where to chose …

hi robert, click on the ‘options’ field, it should produce a drop down of choices, assuming these aren’t configured else where.

mind you, i don’t think this will work after all. when i tested it two different patients were allowed the same id that i typed in.

Dup Check or Dup Checck on only New… or both:

Hi Luis
I tried adding both as u suggested. But it is still letting me add the same pt id no which i have already assigned to another pt.

Without adding a field. Are you using External ID (pubpid)?..could you use this one?

Sorry I am using drivers_license.
But it is still allowing duplicate entries.